feat(phase2c): 群聊与已读回执功能完整实现

Phase 2c 全部 14 个 Task 完成，包含：后端（Go）： - MinIO 文件存储服务集成（Docker + Go SDK + 通用上传 API） - Group 模块完整实现（DAO + Service + Controller + Router + Wire） - 18 个群管理 REST API + 11 个 WS 群事件推送 - 群创建/解散/邀请/踢人/退出/转让群主/设管理员/禁言/全体禁言/群公告/群昵称/免打扰/搜索 - IM Service 扩展（群消息发送/撤回 + @提醒 + 管理员无时限撤回） - 已读回执后端（单聊会话级 last_read_msg_id + 群聊消息级 im_message_reads） - 管理端群组管理（列表/详情/解散） - 数据库迁移（3 张新表 + 2 张表字段扩展）前端（uni-app）： - 群聊 Store + API 封装 + 11 个 WS 事件监听 - 已读回执 UI（单聊已读/未读标记 + 群聊 X人已读 + 已读详情页） - 7 个群聊页面（对话/创建/设置/成员/邀请/审批/搜索） - 会话列表改造（全部/单聊/群聊 Tab + @标记 + 免打扰标识）管理端（Vue 3 + Element Plus）： - 群组列表页（搜索/分页/详情弹窗/解散群聊） - 侧边栏群组管理入口文档同步：进度/架构/设计/API/规范文档全部更新 Made-with: Cursor
2026-03-04 14:58:23 +08:00
parent ad76d9a613
commit 19979da59e
77 changed files with 10053 additions and 490 deletions
--- a/backend/go-service/app/admin/controller/group_manage_controller.go
+++ b/backend/go-service/app/admin/controller/group_manage_controller.go
@@ -0,0 +1,94 @@
+// Package controller 提供 admin 模块的 HTTP 接口处理
+package controller
+
+import (
+	"strconv"
+
+	"github.com/echochat/backend/app/admin/service"
+	"github.com/echochat/backend/pkg/logs"
+	"github.com/echochat/backend/pkg/utils"
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+)
+
+// GroupManageController 管理端群组管理控制器
+type GroupManageController struct {
+	groupManageService *service.GroupManageService
+}
+
+// NewGroupManageController 创建群组管理控制器实例
+func NewGroupManageController(svc *service.GroupManageService) *GroupManageController {
+	return &GroupManageController{groupManageService: svc}
+}
+
+// GetGroupList 获取群组列表
+// GET /api/v1/admin/groups?page=1&page_size=20&keyword=xxx
+func (ctl *GroupManageController) GetGroupList(c *gin.Context) {
+	funcName := "admin.group_manage_controller.GetGroupList"
+	ctx := c.Request.Context()
+
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
+	keyword := c.Query("keyword")
+
+	list, total, err := ctl.groupManageService.ListGroups(ctx, page, pageSize, keyword)
+	if err != nil {
+		logs.Error(ctx, funcName, "获取群组列表失败", zap.Error(err))
+		utils.ResponseError(c, "获取群组列表失败")
+		return
+	}
+
+	logs.Info(ctx, funcName, "获取群组列表成功",
+		zap.Int64("total", total), zap.Int("page", page))
+	utils.ResponseOK(c, gin.H{
+		"list":  list,
+		"total": total,
+	})
+}
+
+// GetGroupDetail 获取群组详情
+// GET /api/v1/admin/groups/:id
+func (ctl *GroupManageController) GetGroupDetail(c *gin.Context) {
+	funcName := "admin.group_manage_controller.GetGroupDetail"
+	ctx := c.Request.Context()
+
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "ID 格式错误")
+		return
+	}
+
+	detail, err := ctl.groupManageService.GetGroupDetail(ctx, id)
+	if err != nil {
+		logs.Error(ctx, funcName, "获取群组详情失败",
+			zap.Int64("group_id", id), zap.Error(err))
+		utils.ResponseError(c, "获取群组详情失败")
+		return
+	}
+
+	logs.Info(ctx, funcName, "获取群组详情成功", zap.Int64("group_id", id))
+	utils.ResponseOK(c, detail)
+}
+
+// DissolveGroup 解散群聊
+// DELETE /api/v1/admin/groups/:id
+func (ctl *GroupManageController) DissolveGroup(c *gin.Context) {
+	funcName := "admin.group_manage_controller.DissolveGroup"
+	ctx := c.Request.Context()
+
+	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "ID 格式错误")
+		return
+	}
+
+	if err := ctl.groupManageService.DissolveGroup(ctx, id); err != nil {
+		logs.Error(ctx, funcName, "解散群聊失败",
+			zap.Int64("group_id", id), zap.Error(err))
+		utils.ResponseError(c, "解散群聊失败")
+		return
+	}
+
+	logs.Info(ctx, funcName, "解散群聊成功", zap.Int64("group_id", id))
+	utils.ResponseOK(c, nil)
+}
--- a/backend/go-service/app/admin/provider.go
+++ b/backend/go-service/app/admin/provider.go
@@ -18,4 +18,6 @@ var AdminSet = wire.NewSet(
 	controller.NewOnlineController,
 	service.NewContactManageService,
 	controller.NewContactManageController,
+	service.NewGroupManageService,
+	controller.NewGroupManageController,
 )
--- a/backend/go-service/app/admin/router.go
+++ b/backend/go-service/app/admin/router.go
@@ -15,6 +15,7 @@ func RegisterRoutes(
 	userCtrl *controller.UserManageController,
 	onlineCtrl *controller.OnlineController,
 	contactManageCtrl *controller.ContactManageController,
+	groupManageCtrl *controller.GroupManageController,
 	jwtAuth gin.HandlerFunc,
 ) {
 	// 管理端路由组：JWT 认证 + admin/super_admin 角色检查
@@ -38,5 +39,10 @@ func RegisterRoutes(
 		// 好友关系管理
 		adminGroup.GET("/contacts", contactManageCtrl.GetAllContacts)
 		adminGroup.DELETE("/contacts/:id", contactManageCtrl.DeleteContact)
+
+		// 群组管理
+		adminGroup.GET("/groups", groupManageCtrl.GetGroupList)
+		adminGroup.GET("/groups/:id", groupManageCtrl.GetGroupDetail)
+		adminGroup.DELETE("/groups/:id", groupManageCtrl.DissolveGroup)
 	}
 }
--- a/backend/go-service/app/admin/service/group_manage_service.go
+++ b/backend/go-service/app/admin/service/group_manage_service.go
@@ -0,0 +1,247 @@
+// Package service 提供 admin 模块的核心业务逻辑
+package service
+
+import (
+	"context"
+	"math"
+	"strconv"
+
+	groupDAO "github.com/echochat/backend/app/group/dao"
+	groupModel "github.com/echochat/backend/app/group/model"
+	"github.com/echochat/backend/pkg/logs"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+)
+
+// GroupManageService 管理端群组管理服务
+type GroupManageService struct {
+	db       *gorm.DB
+	groupDAO *groupDAO.GroupDAO
+}
+
+// NewGroupManageService 创建群组管理服务实例
+func NewGroupManageService(db *gorm.DB, groupDAO *groupDAO.GroupDAO) *GroupManageService {
+	return &GroupManageService{db: db, groupDAO: groupDAO}
+}
+
+// GroupListItem 管理端群组列表项
+type GroupListItem struct {
+	ID             int64  `json:"id"`
+	ConversationID int64  `json:"conversation_id"`
+	Name           string `json:"name"`
+	Avatar         string `json:"avatar"`
+	OwnerID        int64  `json:"owner_id"`
+	OwnerName      string `json:"owner_name"`
+	MemberCount    int64  `json:"member_count"`
+	MaxMembers     int    `json:"max_members"`
+	Status         int    `json:"status"`
+	IsAllMuted     bool   `json:"is_all_muted"`
+	CreatedAt      string `json:"created_at"`
+}
+
+// GroupDetailInfo 管理端群组详情
+type GroupDetailInfo struct {
+	GroupListItem
+	Notice     string            `json:"notice"`
+	IsSearchable bool            `json:"is_searchable"`
+	Members    []GroupMemberInfo `json:"members"`
+}
+
+// GroupMemberInfo 群成员信息
+type GroupMemberInfo struct {
+	UserID   int64  `json:"user_id"`
+	Username string `json:"username"`
+	Nickname string `json:"nickname"`
+	Role     int    `json:"role"`
+	IsMuted  bool   `json:"is_muted"`
+	JoinedAt string `json:"joined_at"`
+}
+
+// ListGroups 获取群组列表（分页 + 搜索）
+func (s *GroupManageService) ListGroups(ctx context.Context, page, pageSize int, keyword string) ([]GroupListItem, int64, error) {
+	funcName := "service.group_manage_service.ListGroups"
+	logs.Info(ctx, funcName, "获取群组列表",
+		zap.Int("page", page), zap.Int("page_size", pageSize), zap.String("keyword", keyword))
+
+	if page < 1 {
+		page = 1
+	}
+	if pageSize < 1 || pageSize > 100 {
+		pageSize = 20
+	}
+
+	offset := (page - 1) * pageSize
+
+	var groups []groupModel.Group
+	var total int64
+
+	query := s.db.WithContext(ctx).Model(&groupModel.Group{})
+	if keyword != "" {
+		query = query.Where("name ILIKE ?", "%"+keyword+"%")
+	}
+
+	if err := query.Count(&total).Error; err != nil {
+		return nil, 0, err
+	}
+
+	if err := query.Order("created_at DESC").Offset(offset).Limit(pageSize).Find(&groups).Error; err != nil {
+		return nil, 0, err
+	}
+
+	// 批量查询群主名称，避免 N+1
+	ownerIDs := make([]int64, 0, len(groups))
+	convIDs := make([]int64, 0, len(groups))
+	for _, g := range groups {
+		ownerIDs = append(ownerIDs, g.OwnerID)
+		convIDs = append(convIDs, g.ConversationID)
+	}
+	ownerNameMap := s.batchGetUsernames(ctx, ownerIDs)
+	memberCountMap := s.batchGetMemberCounts(ctx, convIDs)
+
+	list := make([]GroupListItem, 0, len(groups))
+	for _, g := range groups {
+		list = append(list, GroupListItem{
+			ID:             g.ID,
+			ConversationID: g.ConversationID,
+			Name:           g.Name,
+			Avatar:         g.Avatar,
+			OwnerID:        g.OwnerID,
+			OwnerName:      ownerNameMap[g.OwnerID],
+			MemberCount:    memberCountMap[g.ConversationID],
+			MaxMembers:     g.MaxMembers,
+			Status:         g.Status,
+			IsAllMuted:     g.IsAllMuted,
+			CreatedAt:      g.CreatedAt.Format("2006-01-02 15:04:05"),
+		})
+	}
+
+	totalPages := int(math.Ceil(float64(total) / float64(pageSize)))
+	logs.Info(ctx, funcName, "获取群组列表成功",
+		zap.Int64("total", total), zap.Int("total_pages", totalPages))
+
+	return list, total, nil
+}
+
+// GetGroupDetail 获取群组详情（含成员列表）
+func (s *GroupManageService) GetGroupDetail(ctx context.Context, groupID int64) (*GroupDetailInfo, error) {
+	funcName := "service.group_manage_service.GetGroupDetail"
+	logs.Info(ctx, funcName, "获取群组详情", zap.Int64("group_id", groupID))
+
+	group, err := s.groupDAO.GetByID(ctx, groupID)
+	if err != nil {
+		return nil, err
+	}
+
+	memberCount, _ := s.groupDAO.GetMemberCount(ctx, group.ConversationID)
+	ownerName := s.getUsername(ctx, group.OwnerID)
+
+	members, err := s.groupDAO.GetMembers(ctx, group.ConversationID)
+	if err != nil {
+		return nil, err
+	}
+
+	memberInfos := make([]GroupMemberInfo, 0, len(members))
+	for _, m := range members {
+		username := s.getUsername(ctx, m.UserID)
+		memberInfos = append(memberInfos, GroupMemberInfo{
+			UserID:   m.UserID,
+			Username: username,
+			Nickname: m.Nickname,
+			Role:     m.Role,
+			IsMuted:  m.IsMuted,
+			JoinedAt: m.JoinedAt.Format("2006-01-02 15:04:05"),
+		})
+	}
+
+	detail := &GroupDetailInfo{
+		GroupListItem: GroupListItem{
+			ID:             group.ID,
+			ConversationID: group.ConversationID,
+			Name:           group.Name,
+			Avatar:         group.Avatar,
+			OwnerID:        group.OwnerID,
+			OwnerName:      ownerName,
+			MemberCount:    memberCount,
+			MaxMembers:     group.MaxMembers,
+			Status:         group.Status,
+			IsAllMuted:     group.IsAllMuted,
+			CreatedAt:      group.CreatedAt.Format("2006-01-02 15:04:05"),
+		},
+		Notice:       group.Notice,
+		IsSearchable: group.IsSearchable,
+		Members:      memberInfos,
+	}
+
+	return detail, nil
+}
+
+// DissolveGroup 管理端解散群聊
+func (s *GroupManageService) DissolveGroup(ctx context.Context, groupID int64) error {
+	funcName := "service.group_manage_service.DissolveGroup"
+	logs.Info(ctx, funcName, "管理端解散群聊", zap.Int64("group_id", groupID))
+	return s.groupDAO.DissolveGroup(ctx, groupID)
+}
+
+// getUsername 通过用户 ID 获取用户名（优先昵称，其次用户名）
+func (s *GroupManageService) getUsername(ctx context.Context, userID int64) string {
+	var username string
+	s.db.WithContext(ctx).Table("auth_users").
+		Where("id = ?", userID).
+		Pluck("COALESCE(NULLIF(nickname, ''), username)", &username)
+	if username == "" {
+		return strconv.FormatInt(userID, 10)
+	}
+	return username
+}
+
+// batchGetUsernames 批量查询用户名，返回 userID → 显示名 映射
+func (s *GroupManageService) batchGetUsernames(ctx context.Context, userIDs []int64) map[int64]string {
+	result := make(map[int64]string, len(userIDs))
+	if len(userIDs) == 0 {
+		return result
+	}
+
+	type row struct {
+		ID       int64  `gorm:"column:id"`
+		Username string `gorm:"column:display_name"`
+	}
+	var rows []row
+	s.db.WithContext(ctx).Table("auth_users").
+		Select("id, COALESCE(NULLIF(nickname, ''), username) AS display_name").
+		Where("id IN ?", userIDs).
+		Find(&rows)
+
+	for _, r := range rows {
+		result[r.ID] = r.Username
+	}
+	for _, uid := range userIDs {
+		if _, ok := result[uid]; !ok {
+			result[uid] = strconv.FormatInt(uid, 10)
+		}
+	}
+	return result
+}
+
+// batchGetMemberCounts 批量查询会话的成员数，返回 conversationID → count 映射
+func (s *GroupManageService) batchGetMemberCounts(ctx context.Context, conversationIDs []int64) map[int64]int64 {
+	result := make(map[int64]int64, len(conversationIDs))
+	if len(conversationIDs) == 0 {
+		return result
+	}
+
+	type row struct {
+		ConversationID int64 `gorm:"column:conversation_id"`
+		Count          int64 `gorm:"column:cnt"`
+	}
+	var rows []row
+	s.db.WithContext(ctx).Table("im_conversation_members").
+		Select("conversation_id, COUNT(*) AS cnt").
+		Where("conversation_id IN ?", conversationIDs).
+		Group("conversation_id").
+		Find(&rows)
+
+	for _, r := range rows {
+		result[r.ConversationID] = r.Count
+	}
+	return result
+}
--- a/backend/go-service/app/constants/group.go
+++ b/backend/go-service/app/constants/group.go
@@ -0,0 +1,46 @@
+package constants
+
+// 群聊状态
+const (
+	GroupStatusNormal    = 1 // 正常
+	GroupStatusDissolved = 2 // 已解散
+)
+
+// GroupStatusMap 群聊状态中文映射
+var GroupStatusMap = map[int]string{
+	GroupStatusNormal:    "正常",
+	GroupStatusDissolved: "已解散",
+}
+
+// 群成员角色（im_conversation_members.role）
+const (
+	GroupRoleNormal = 0 // 普通成员
+	GroupRoleAdmin  = 1 // 管理员
+	GroupRoleOwner  = 2 // 群主
+)
+
+// GroupRoleMap 群成员角色中文映射
+var GroupRoleMap = map[int]string{
+	GroupRoleNormal: "普通成员",
+	GroupRoleAdmin:  "管理员",
+	GroupRoleOwner:  "群主",
+}
+
+// 入群申请状态（im_group_join_requests.status）
+const (
+	JoinRequestStatusPending  = 0 // 待审批
+	JoinRequestStatusApproved = 1 // 通过
+	JoinRequestStatusRejected = 2 // 拒绝
+)
+
+// JoinRequestStatusMap 入群申请状态中文映射
+var JoinRequestStatusMap = map[int]string{
+	JoinRequestStatusPending:  "待审批",
+	JoinRequestStatusApproved: "通过",
+	JoinRequestStatusRejected: "拒绝",
+}
+
+// 群聊默认配置
+const (
+	GroupDefaultMaxMembers = 200 // 默认最大成员数
+)
--- a/backend/go-service/app/constants/im.go
+++ b/backend/go-service/app/constants/im.go
@@ -14,20 +14,22 @@ var ConversationTypeMap = map[int]string{

 // 消息类型
 const (
-	MessageTypeText  = 1 // 文本消息
-	MessageTypeImage = 2 // 图片消息（预留）
-	MessageTypeVoice = 3 // 语音消息（预留）
-	MessageTypeVideo = 4 // 视频消息（预留）
-	MessageTypeFile  = 5 // 文件消息（预留）
+	MessageTypeText   = 1  // 文本消息
+	MessageTypeImage  = 2  // 图片消息（预留）
+	MessageTypeVoice  = 3  // 语音消息（预留）
+	MessageTypeVideo  = 4  // 视频消息（预留）
+	MessageTypeFile   = 5  // 文件消息（预留）
+	MessageTypeSystem = 10 // 系统消息（群聊操作通知）
 )

 // MessageTypeMap 消息类型中文映射
 var MessageTypeMap = map[int]string{
-	MessageTypeText:  "文本",
-	MessageTypeImage: "图片",
-	MessageTypeVoice: "语音",
-	MessageTypeVideo: "视频",
-	MessageTypeFile:  "文件",
+	MessageTypeText:   "文本",
+	MessageTypeImage:  "图片",
+	MessageTypeVoice:  "语音",
+	MessageTypeVideo:  "视频",
+	MessageTypeFile:   "文件",
+	MessageTypeSystem: "系统消息",
 }

 // 消息状态
--- a/backend/go-service/app/dto/group_dto.go
+++ b/backend/go-service/app/dto/group_dto.go
@@ -0,0 +1,177 @@
+package dto
+
+// ====== 群聊管理 DTO ======
+
+// CreateGroupRequest 创建群聊请求
+// POST /api/v1/groups
+type CreateGroupRequest struct {
+	Name      string  `json:"name" binding:"required,max=100"`  // 群名称
+	MemberIDs []int64 `json:"member_ids" binding:"required"`    // 初始成员用户 ID 列表（不含创建者自身）
+	Avatar    string  `json:"avatar"`                           // 群头像 URL（可选）
+}
+
+// UpdateGroupRequest 更新群信息请求
+// PUT /api/v1/groups/:id
+type UpdateGroupRequest struct {
+	Name         *string `json:"name"`          // 群名称
+	Avatar       *string `json:"avatar"`        // 群头像 URL
+	Notice       *string `json:"notice"`        // 群公告
+	IsSearchable *bool   `json:"is_searchable"` // 是否可被搜索
+}
+
+// GroupDTO 群聊信息传输对象（返回给前端）
+type GroupDTO struct {
+	ID             int64  `json:"id"`              // 群 ID
+	ConversationID int64  `json:"conversation_id"` // 关联会话 ID
+	Name           string `json:"name"`            // 群名称
+	Avatar         string `json:"avatar"`          // 群头像
+	OwnerID        int64  `json:"owner_id"`        // 群主用户 ID
+	Notice         string `json:"notice"`          // 群公告
+	MaxMembers     int    `json:"max_members"`     // 最大成员数
+	MemberCount    int    `json:"member_count"`    // 当前成员数
+	IsSearchable   bool   `json:"is_searchable"`   // 是否可被搜索
+	IsAllMuted     bool   `json:"is_all_muted"`    // 是否全体禁言
+	Status         int    `json:"status"`          // 群状态：1=正常，2=已解散
+	CreatedAt      string `json:"created_at"`      // 创建时间
+}
+
+// ====== 群成员 DTO ======
+
+// GroupMemberDTO 群成员信息传输对象
+type GroupMemberDTO struct {
+	UserID         int64  `json:"user_id"`          // 用户 ID
+	Nickname       string `json:"nickname"`         // 群内昵称
+	UserNickname   string `json:"user_nickname"`    // 用户原始昵称
+	Avatar         string `json:"avatar"`           // 用户头像
+	Role           int    `json:"role"`             // 角色：0=普通成员，1=管理员，2=群主
+	IsMuted        bool   `json:"is_muted"`         // 是否被禁言
+	JoinedAt       string `json:"joined_at"`        // 加入时间
+}
+
+// InviteMembersRequest 邀请入群请求
+// POST /api/v1/groups/:id/members
+type InviteMembersRequest struct {
+	UserIDs []int64 `json:"user_ids" binding:"required"` // 被邀请的用户 ID 列表
+}
+
+// SetRoleRequest 设置/取消管理员请求
+// PUT /api/v1/groups/:id/members/:uid/role
+type SetRoleRequest struct {
+	Role int `json:"role" binding:"oneof=0 1"` // 目标角色：0=普通成员，1=管理员
+}
+
+// MuteRequest 禁言/解除禁言请求
+// PUT /api/v1/groups/:id/members/:uid/mute
+type MuteRequest struct {
+	IsMuted bool `json:"is_muted"` // true=禁言, false=解除
+}
+
+// TransferOwnerRequest 转让群主请求
+// PUT /api/v1/groups/:id/transfer
+type TransferOwnerRequest struct {
+	NewOwnerID int64 `json:"new_owner_id" binding:"required"` // 新群主用户 ID
+}
+
+// UpdateNicknameRequest 修改群昵称请求
+// PUT /api/v1/groups/:id/members/me/nickname
+type UpdateNicknameRequest struct {
+	Nickname string `json:"nickname" binding:"max=50"` // 群内昵称
+}
+
+// ====== 入群申请 DTO ======
+
+// JoinGroupRequest 申请入群请求
+// POST /api/v1/groups/:id/join-requests
+type JoinGroupRequest struct {
+	Message string `json:"message"` // 申请附言
+}
+
+// ReviewJoinRequest 审批入群申请请求
+// PUT /api/v1/groups/:id/join-requests/:rid
+type ReviewJoinRequest struct {
+	Action string `json:"action" binding:"required,oneof=approve reject"` // 操作：approve=通过, reject=拒绝
+}
+
+// JoinRequestDTO 入群申请传输对象
+type JoinRequestDTO struct {
+	ID           int64  `json:"id"`            // 申请 ID
+	GroupID      int64  `json:"group_id"`      // 群 ID
+	UserID       int64  `json:"user_id"`       // 申请人用户 ID
+	UserNickname string `json:"user_nickname"` // 申请人昵称
+	UserAvatar   string `json:"user_avatar"`   // 申请人头像
+	Message      string `json:"message"`       // 申请附言
+	Status       int    `json:"status"`        // 状态：0=待审批，1=通过，2=拒绝
+	CreatedAt    string `json:"created_at"`    // 申请时间
+}
+
+// ====== 群搜索 DTO ======
+
+// SearchGroupRequest 搜索群聊请求
+// GET /api/v1/groups/search?keyword=xx&page=1&page_size=20
+type SearchGroupRequest struct {
+	Keyword  string `form:"keyword" binding:"required"` // 搜索关键词
+	Page     int    `form:"page"`                       // 页码（默认 1）
+	PageSize int    `form:"page_size"`                  // 每页数量（默认 20）
+}
+
+// SearchGroupResponse 搜索群聊响应
+type SearchGroupResponse struct {
+	List  []GroupDTO `json:"list"`  // 搜索结果
+	Total int64      `json:"total"` // 总数
+}
+
+// ====== 已读回执 DTO ======
+
+// MarkGroupReadRequest 群聊标记已读请求（WS 事件 im.message.read 的 data 字段）
+type MarkGroupReadRequest struct {
+	ConversationID int64   `json:"conversation_id"` // 会话 ID
+	MessageIDs     []int64 `json:"message_ids"`     // 已读消息 ID 列表
+}
+
+// MessageReadCountDTO 消息已读计数传输对象
+type MessageReadCountDTO struct {
+	MessageID int64 `json:"message_id"` // 消息 ID
+	ReadCount int   `json:"read_count"` // 已读人数
+}
+
+// MessageReadDetailDTO 消息已读详情传输对象
+type MessageReadDetailDTO struct {
+	UserID       int64  `json:"user_id"`       // 已读用户 ID
+	UserNickname string `json:"user_nickname"` // 用户昵称
+	UserAvatar   string `json:"user_avatar"`   // 用户头像
+	ReadAt       string `json:"read_at"`       // 已读时间
+}
+
+// GetReadDetailRequest 获取已读详情请求
+// GET /api/v1/im/messages/:id/reads?page=1&page_size=20
+type GetReadDetailRequest struct {
+	Page     int `form:"page"`      // 页码（默认 1）
+	PageSize int `form:"page_size"` // 每页数量（默认 20）
+}
+
+// GetReadDetailResponse 获取已读详情响应
+type GetReadDetailResponse struct {
+	ReadList   []MessageReadDetailDTO `json:"read_list"`   // 已读用户列表
+	UnreadList []MessageReadDetailDTO `json:"unread_list"` // 未读用户列表
+	ReadCount  int                    `json:"read_count"`  // 已读人数
+	TotalCount int                    `json:"total_count"` // 群成员总数（不含发送者）
+}
+
+// ====== 免打扰 DTO ======
+
+// SetDoNotDisturbRequest 设置/取消免打扰请求
+// PUT /api/v1/im/conversations/:id/dnd
+type SetDoNotDisturbRequest struct {
+	IsDoNotDisturb bool `json:"is_do_not_disturb"` // true=开启, false=关闭
+}
+
+// ====== 跨模块接口数据传输 ======
+
+// GroupBrief 群简要信息（IM 模块通过 GroupInfoGetter 接口获取）
+type GroupBrief struct {
+	ID         int64  `json:"id"`
+	Name       string `json:"name"`
+	Avatar     string `json:"avatar"`
+	IsAllMuted bool   `json:"is_all_muted"`
+	Status     int    `json:"status"`
+}
--- a/backend/go-service/app/dto/im_dto.go
+++ b/backend/go-service/app/dto/im_dto.go
@@ -4,23 +4,25 @@ package dto

 // SendMessageRequest 发送消息请求（WS 事件 im.message.send 的 data 字段）
 type SendMessageRequest struct {
-	ConversationID int64  `json:"conversation_id"`  // 会话 ID（与 TargetUserID 二选一）
-	TargetUserID   int64  `json:"target_user_id"`   // 对方用户 ID（首次发消息时使用，自动创建会话）
-	Type           int    `json:"type"`              // 消息类型：1=文本
-	Content        string `json:"content"`           // 消息内容
-	ClientMsgID    string `json:"client_msg_id"`     // 客户端消息唯一 ID，用于幂等去重
+	ConversationID int64   `json:"conversation_id"`  // 会话 ID（与 TargetUserID 二选一）
+	TargetUserID   int64   `json:"target_user_id"`   // 对方用户 ID（首次发消息时使用，自动创建会话）
+	Type           int     `json:"type"`              // 消息类型：1=文本
+	Content        string  `json:"content"`           // 消息内容
+	ClientMsgID    string  `json:"client_msg_id"`     // 客户端消息唯一 ID，用于幂等去重
+	AtUserIDs      []int64 `json:"at_user_ids"`       // @提醒用户 ID 列表（含 0 表示 @所有人）
 }

 // MessageDTO 消息传输对象（返回给前端）
 type MessageDTO struct {
-	ID             int64  `json:"id"`              // 消息 ID
-	ConversationID int64  `json:"conversation_id"` // 所属会话 ID
-	SenderID       int64  `json:"sender_id"`       // 发送者用户 ID
-	Type           int    `json:"type"`            // 消息类型
-	Content        string `json:"content"`         // 消息内容
-	Status         int    `json:"status"`          // 消息状态：1=正常，2=已撤回
-	ClientMsgID    string `json:"client_msg_id"`   // 客户端消息 ID
-	CreatedAt      string `json:"created_at"`      // 发送时间
+	ID             int64   `json:"id"`              // 消息 ID
+	ConversationID int64   `json:"conversation_id"` // 所属会话 ID
+	SenderID       int64   `json:"sender_id"`       // 发送者用户 ID
+	Type           int     `json:"type"`            // 消息类型
+	Content        string  `json:"content"`         // 消息内容
+	Status         int     `json:"status"`          // 消息状态：1=正常，2=已撤回
+	ClientMsgID    string  `json:"client_msg_id"`   // 客户端消息 ID
+	AtUserIDs      []int64 `json:"at_user_ids"`     // @提醒用户 ID 列表
+	CreatedAt      string  `json:"created_at"`      // 发送时间
 }

 // RecallMessageRequest 撤回消息请求（WS 事件 im.message.recall 的 data 字段）
@@ -32,16 +34,19 @@ type RecallMessageRequest struct {

 // ConversationDTO 会话列表条目（返回给前端）
 type ConversationDTO struct {
-	ID              int64  `json:"id"`                // 会话 ID
-	Type            int    `json:"type"`              // 会话类型：1=单聊
-	PeerUserID      int64  `json:"peer_user_id"`      // 单聊对方用户 ID
-	PeerNickname    string `json:"peer_nickname"`     // 对方昵称
-	PeerAvatar      string `json:"peer_avatar"`       // 对方头像
-	LastMsgContent  string `json:"last_msg_content"`  // 最后消息预览
-	LastMsgTime     string `json:"last_msg_time"`     // 最后消息时间
+	ID              int64  `json:"id"`                 // 会话 ID
+	Type            int    `json:"type"`               // 会话类型：1=单聊，2=群聊
+	PeerUserID      int64  `json:"peer_user_id"`       // 单聊对方用户 ID（群聊为 0）
+	PeerNickname    string `json:"peer_nickname"`      // 对方昵称（群聊时为群名称）
+	PeerAvatar      string `json:"peer_avatar"`        // 对方头像（群聊时为群头像）
+	LastMsgContent  string `json:"last_msg_content"`   // 最后消息预览
+	LastMsgTime     string `json:"last_msg_time"`      // 最后消息时间
 	LastMsgSenderID *int64 `json:"last_msg_sender_id"` // 最后消息发送者 ID
-	IsPinned        bool   `json:"is_pinned"`         // 是否置顶
-	UnreadCount     int    `json:"unread_count"`      // 未读消息数
+	IsPinned        bool   `json:"is_pinned"`          // 是否置顶
+	UnreadCount     int    `json:"unread_count"`       // 未读消息数
+	GroupID         int64  `json:"group_id,omitempty"` // 群聊 ID（仅 type=2 有值）
+	IsDoNotDisturb  bool   `json:"is_do_not_disturb"`  // 是否免打扰
+	AtMeCount       int    `json:"at_me_count"`        // 被@提醒未读计数
 }

 // ConversationListResponse 会话列表响应
--- a/backend/go-service/app/file/controller/file_controller.go
+++ b/backend/go-service/app/file/controller/file_controller.go
@@ -0,0 +1,70 @@
+// Package controller 提供文件上传模块的 HTTP 接口处理
+package controller
+
+import (
+	"github.com/echochat/backend/app/file/service"
+	"github.com/echochat/backend/pkg/middleware"
+	"github.com/echochat/backend/pkg/utils"
+	"github.com/gin-gonic/gin"
+)
+
+const maxUploadSize = 10 << 20 // 10 MB
+
+// FileController 文件上传控制器
+type FileController struct {
+	fileService *service.FileService
+}
+
+// NewFileController 创建文件上传控制器
+func NewFileController(fileService *service.FileService) *FileController {
+	return &FileController{fileService: fileService}
+}
+
+// Upload 处理文件上传请求
+// POST /api/v1/upload
+// 支持 multipart/form-data，字段名为 "file"
+func (ctl *FileController) Upload(c *gin.Context) {
+	ctx := c.Request.Context()
+	_, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	fileHeader, err := c.FormFile("file")
+	if err != nil {
+		utils.ResponseBadRequest(c, "请选择要上传的文件")
+		return
+	}
+
+	if fileHeader.Size > maxUploadSize {
+		utils.ResponseBadRequest(c, "文件大小不能超过 10MB")
+		return
+	}
+
+	result, err := ctl.fileService.Upload(ctx, fileHeader)
+	if err != nil {
+		ctl.handleError(c, err, "文件上传失败")
+		return
+	}
+
+	utils.ResponseOK(c, result)
+}
+
+// handleError 统一业务错误映射
+// 已知业务错误 → 返回 Service 层定义的具体提示
+// 未知错误 → 返回 fallbackMsg（未传则默认"服务器内部错误"）
+func (ctl *FileController) handleError(c *gin.Context, err error, fallbackMsg ...string) {
+	switch err {
+	case service.ErrFileOpen:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrUploadFailed:
+		utils.ResponseError(c, err.Error())
+	default:
+		msg := "服务器内部错误"
+		if len(fallbackMsg) > 0 && fallbackMsg[0] != "" {
+			msg = fallbackMsg[0]
+		}
+		utils.ResponseError(c, msg)
+	}
+}
--- a/backend/go-service/app/file/provider.go
+++ b/backend/go-service/app/file/provider.go
@@ -0,0 +1,14 @@
+// Package file 文件上传模块 Wire 依赖注入配置
+package file
+
+import (
+	"github.com/echochat/backend/app/file/controller"
+	"github.com/echochat/backend/app/file/service"
+	"github.com/google/wire"
+)
+
+// FileSet 文件上传模块 Wire Provider Set
+var FileSet = wire.NewSet(
+	service.NewFileService,
+	controller.NewFileController,
+)
--- a/backend/go-service/app/file/router.go
+++ b/backend/go-service/app/file/router.go
@@ -0,0 +1,16 @@
+// Package file 文件上传模块路由注册
+package file
+
+import (
+	"github.com/echochat/backend/app/file/controller"
+	"github.com/gin-gonic/gin"
+)
+
+// RegisterRoutes 注册文件上传模块的所有路由（需要 JWT 中间件）
+func RegisterRoutes(r *gin.Engine, ctrl *controller.FileController, jwtAuth gin.HandlerFunc) {
+	authed := r.Group("/api/v1")
+	authed.Use(jwtAuth)
+	{
+		authed.POST("/upload", ctrl.Upload)
+	}
+}
--- a/backend/go-service/app/file/service/file_service.go
+++ b/backend/go-service/app/file/service/file_service.go
@@ -0,0 +1,90 @@
+// Package service 提供文件上传模块的业务逻辑
+// 封装 MinIO 对象存储的上传操作，返回可访问的文件 URL
+package service
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"mime/multipart"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/echochat/backend/config"
+	"github.com/echochat/backend/pkg/logs"
+	"github.com/google/uuid"
+	"github.com/minio/minio-go/v7"
+	"go.uber.org/zap"
+)
+
+var (
+	ErrFileOpen     = errors.New("打开上传文件失败")
+	ErrUploadFailed = errors.New("文件上传失败")
+)
+
+// FileService 文件上传服务
+type FileService struct {
+	minioClient *minio.Client
+	minioCfg    *config.MinioConfig
+}
+
+// NewFileService 创建文件上传服务实例
+func NewFileService(client *minio.Client, cfg *config.MinioConfig) *FileService {
+	return &FileService{
+		minioClient: client,
+		minioCfg:    cfg,
+	}
+}
+
+// UploadResult 文件上传结果
+type UploadResult struct {
+	URL      string `json:"url"`
+	FileName string `json:"file_name"`
+	Size     int64  `json:"size"`
+}
+
+// Upload 上传文件到 MinIO，返回文件访问 URL
+// 文件按日期目录组织：uploads/2026/03/04/{uuid}.{ext}
+func (s *FileService) Upload(ctx context.Context, fileHeader *multipart.FileHeader) (*UploadResult, error) {
+	funcName := "service.file_service.Upload"
+	logs.Info(ctx, funcName, "上传文件",
+		zap.String("file_name", fileHeader.Filename),
+		zap.Int64("size", fileHeader.Size))
+
+	file, err := fileHeader.Open()
+	if err != nil {
+		logs.Error(ctx, funcName, "打开上传文件失败", zap.Error(err))
+		return nil, ErrFileOpen
+	}
+	defer file.Close()
+
+	ext := strings.ToLower(filepath.Ext(fileHeader.Filename))
+	now := time.Now()
+	objectName := fmt.Sprintf("uploads/%s/%s%s", now.Format("2006/01/02"), uuid.New().String(), ext)
+
+	contentType := fileHeader.Header.Get("Content-Type")
+	if contentType == "" {
+		contentType = "application/octet-stream"
+	}
+
+	_, err = s.minioClient.PutObject(ctx, s.minioCfg.Bucket, objectName, file, fileHeader.Size, minio.PutObjectOptions{
+		ContentType: contentType,
+	})
+	if err != nil {
+		logs.Error(ctx, funcName, "上传文件到 MinIO 失败", zap.Error(err))
+		return nil, ErrUploadFailed
+	}
+
+	scheme := "http"
+	if s.minioCfg.UseSSL {
+		scheme = "https"
+	}
+	url := fmt.Sprintf("%s://%s/%s/%s", scheme, s.minioCfg.Endpoint, s.minioCfg.Bucket, objectName)
+
+	return &UploadResult{
+		URL:      url,
+		FileName: fileHeader.Filename,
+		Size:     fileHeader.Size,
+	}, nil
+}
--- a/backend/go-service/app/group/controller/group_controller.go
+++ b/backend/go-service/app/group/controller/group_controller.go
@@ -0,0 +1,542 @@
+// Package controller 提供 group 模块的 HTTP 接口处理
+package controller
+
+import (
+	"strconv"
+
+	"github.com/echochat/backend/app/dto"
+	"github.com/echochat/backend/app/group/service"
+	"github.com/echochat/backend/pkg/middleware"
+	"github.com/echochat/backend/pkg/utils"
+	"github.com/gin-gonic/gin"
+)
+
+// GroupController 群聊管理控制器（REST API）
+type GroupController struct {
+	groupService *service.GroupService
+}
+
+// NewGroupController 创建 GroupController 实例
+func NewGroupController(groupService *service.GroupService) *GroupController {
+	return &GroupController{groupService: groupService}
+}
+
+// CreateGroup 创建群聊
+// POST /api/v1/groups
+func (ctl *GroupController) CreateGroup(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	var req dto.CreateGroupRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	result, err := ctl.groupService.CreateGroup(ctx, userID, &req)
+	if err != nil {
+		ctl.handleError(c, err, "创建群聊失败")
+		return
+	}
+	utils.ResponseOK(c, result)
+}
+
+// GetGroupDetail 获取群详情
+// GET /api/v1/groups/:id
+func (ctl *GroupController) GetGroupDetail(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	result, err := ctl.groupService.GetGroupDetail(ctx, userID, groupID)
+	if err != nil {
+		ctl.handleError(c, err, "获取群详情失败")
+		return
+	}
+	utils.ResponseOK(c, result)
+}
+
+// UpdateGroup 更新群信息
+// PUT /api/v1/groups/:id
+func (ctl *GroupController) UpdateGroup(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	var req dto.UpdateGroupRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.UpdateGroup(ctx, userID, groupID, &req); err != nil {
+		ctl.handleError(c, err, "更新群信息失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// DissolveGroup 解散群聊
+// DELETE /api/v1/groups/:id
+func (ctl *GroupController) DissolveGroup(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	if err := ctl.groupService.DissolveGroup(ctx, userID, groupID); err != nil {
+		ctl.handleError(c, err, "解散群聊失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// GetMembers 获取群成员列表
+// GET /api/v1/groups/:id/members
+func (ctl *GroupController) GetMembers(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	result, err := ctl.groupService.GetMembers(ctx, userID, groupID)
+	if err != nil {
+		ctl.handleError(c, err, "获取成员列表失败")
+		return
+	}
+	utils.ResponseOK(c, result)
+}
+
+// InviteMembers 邀请入群
+// POST /api/v1/groups/:id/members
+func (ctl *GroupController) InviteMembers(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	var req dto.InviteMembersRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.InviteMembers(ctx, userID, groupID, req.UserIDs); err != nil {
+		ctl.handleError(c, err, "邀请入群失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// KickMember 踢出成员
+// DELETE /api/v1/groups/:id/members/:uid
+func (ctl *GroupController) KickMember(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	targetID, err := strconv.ParseInt(c.Param("uid"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "用户 ID 格式错误")
+		return
+	}
+
+	if err := ctl.groupService.KickMember(ctx, userID, groupID, targetID); err != nil {
+		ctl.handleError(c, err, "踢出成员失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// SetMemberRole 设置/取消管理员
+// PUT /api/v1/groups/:id/members/:uid/role
+func (ctl *GroupController) SetMemberRole(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	targetID, err := strconv.ParseInt(c.Param("uid"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "用户 ID 格式错误")
+		return
+	}
+
+	var req dto.SetRoleRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.SetMemberRole(ctx, userID, groupID, targetID, req.Role); err != nil {
+		ctl.handleError(c, err, "设置角色失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// MuteMember 禁言/解除禁言
+// PUT /api/v1/groups/:id/members/:uid/mute
+func (ctl *GroupController) MuteMember(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	targetID, err := strconv.ParseInt(c.Param("uid"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "用户 ID 格式错误")
+		return
+	}
+
+	var req dto.MuteRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.MuteMember(ctx, userID, groupID, targetID, req.IsMuted); err != nil {
+		ctl.handleError(c, err, "操作失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// TransferOwner 转让群主
+// PUT /api/v1/groups/:id/transfer
+func (ctl *GroupController) TransferOwner(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	var req dto.TransferOwnerRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.TransferOwner(ctx, userID, groupID, req.NewOwnerID); err != nil {
+		ctl.handleError(c, err, "转让群主失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// LeaveGroup 退出群聊
+// DELETE /api/v1/groups/:id/members/me
+func (ctl *GroupController) LeaveGroup(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	if err := ctl.groupService.LeaveGroup(ctx, userID, groupID); err != nil {
+		ctl.handleError(c, err, "退出群聊失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// UpdateNickname 修改群内昵称
+// PUT /api/v1/groups/:id/members/me/nickname
+func (ctl *GroupController) UpdateNickname(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	var req dto.UpdateNicknameRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.UpdateNickname(ctx, userID, groupID, req.Nickname); err != nil {
+		ctl.handleError(c, err, "修改昵称失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// SubmitJoinRequest 申请入群
+// POST /api/v1/groups/:id/join-requests
+func (ctl *GroupController) SubmitJoinRequest(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	var req dto.JoinGroupRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.SubmitJoinRequest(ctx, userID, groupID, req.Message); err != nil {
+		ctl.handleError(c, err, "申请入群失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// GetJoinRequests 获取入群申请列表
+// GET /api/v1/groups/:id/join-requests
+func (ctl *GroupController) GetJoinRequests(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	result, err := ctl.groupService.GetJoinRequests(ctx, userID, groupID)
+	if err != nil {
+		ctl.handleError(c, err, "获取入群申请失败")
+		return
+	}
+	utils.ResponseOK(c, result)
+}
+
+// ReviewJoinRequest 审批入群申请
+// PUT /api/v1/groups/:id/join-requests/:rid
+func (ctl *GroupController) ReviewJoinRequest(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	requestID, err := strconv.ParseInt(c.Param("rid"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "申请 ID 格式错误")
+		return
+	}
+
+	var req dto.ReviewJoinRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.ReviewJoinRequest(ctx, userID, groupID, requestID, req.Action); err != nil {
+		ctl.handleError(c, err, "审批失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// SearchGroups 搜索群聊
+// GET /api/v1/groups/search?keyword=xx&page=1&page_size=20
+func (ctl *GroupController) SearchGroups(c *gin.Context) {
+	ctx := c.Request.Context()
+	_, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	var req dto.SearchGroupRequest
+	if err := c.ShouldBindQuery(&req); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	result, err := ctl.groupService.SearchGroups(ctx, &req)
+	if err != nil {
+		ctl.handleError(c, err, "搜索群聊失败")
+		return
+	}
+	utils.ResponseOK(c, result)
+}
+
+// SetAllMuted 设置全体禁言
+// PUT /api/v1/groups/:id/all-mute
+func (ctl *GroupController) SetAllMuted(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	groupID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "群 ID 格式错误")
+		return
+	}
+
+	var body struct {
+		IsAllMuted bool `json:"is_all_muted"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		utils.ResponseBadRequest(c, "参数校验失败: "+err.Error())
+		return
+	}
+
+	if err := ctl.groupService.SetAllMuted(ctx, userID, groupID, body.IsAllMuted); err != nil {
+		ctl.handleError(c, err, "设置全体禁言失败")
+		return
+	}
+	utils.ResponseOK(c, nil)
+}
+
+// handleError 统一业务错误映射
+// 已知业务错误 → 返回 Service 层定义的具体提示
+// 未知错误 → 返回 fallbackMsg（未传则默认"服务器内部错误"）
+func (ctl *GroupController) handleError(c *gin.Context, err error, fallbackMsg ...string) {
+	switch err {
+	case service.ErrGroupNotFound:
+		utils.ResponseNotFound(c, err.Error())
+	case service.ErrGroupDissolved:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrNotGroupMember:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrNotGroupOwner:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrNotGroupAdmin:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrGroupFull:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrAlreadyMember:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrCannotKickHigherRole:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrOwnerCannotLeave:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrCannotMuteSelf:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrAlreadyMuted:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrUserMuted:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrGroupAllMuted:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrPendingRequestExists:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrJoinRequestNotFound:
+		utils.ResponseNotFound(c, err.Error())
+	default:
+		msg := "服务器内部错误"
+		if len(fallbackMsg) > 0 && fallbackMsg[0] != "" {
+			msg = fallbackMsg[0]
+		}
+		utils.ResponseError(c, msg)
+	}
+}
--- a/backend/go-service/app/group/dao/group_dao.go
+++ b/backend/go-service/app/group/dao/group_dao.go
@@ -0,0 +1,346 @@
+// Package dao 提供 group 模块的数据库访问操作
+package dao
+
+import (
+	"context"
+	"time"
+
+	"github.com/echochat/backend/app/constants"
+	"github.com/echochat/backend/app/dto"
+	"github.com/echochat/backend/app/group/model"
+	imModel "github.com/echochat/backend/app/im/model"
+	"github.com/echochat/backend/pkg/logs"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+)
+
+// GroupDAO 群聊数据访问对象
+type GroupDAO struct {
+	db *gorm.DB
+}
+
+// NewGroupDAO 创建 GroupDAO 实例
+func NewGroupDAO(db *gorm.DB) *GroupDAO {
+	return &GroupDAO{db: db}
+}
+
+// CreateGroupWithMembers 在事务中创建群聊（会话 + 群信息 + 群成员）
+// 创建者自动成为群主（role=2）
+func (d *GroupDAO) CreateGroupWithMembers(ctx context.Context, ownerID int64, name, avatar string, memberIDs []int64) (*model.Group, error) {
+	funcName := "dao.group_dao.CreateGroupWithMembers"
+	logs.Info(ctx, funcName, "创建群聊",
+		zap.Int64("owner_id", ownerID), zap.String("name", name), zap.Int("member_count", len(memberIDs)+1))
+
+	var group model.Group
+	err := d.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		conv := &imModel.Conversation{
+			Type:      constants.ConversationTypeGroup,
+			CreatorID: ownerID,
+		}
+		if err := tx.Create(conv).Error; err != nil {
+			logs.Error(ctx, funcName, "创建会话失败", zap.Error(err))
+			return err
+		}
+
+		group = model.Group{
+			ConversationID: conv.ID,
+			Name:           name,
+			Avatar:         avatar,
+			OwnerID:        ownerID,
+			MaxMembers:     constants.GroupDefaultMaxMembers,
+			Status:         constants.GroupStatusNormal,
+		}
+		if err := tx.Create(&group).Error; err != nil {
+			logs.Error(ctx, funcName, "创建群信息失败", zap.Error(err))
+			return err
+		}
+
+		now := time.Now()
+		ownerMember := &imModel.ConversationMember{
+			ConversationID: conv.ID,
+			UserID:         ownerID,
+			Role:           constants.GroupRoleOwner,
+			JoinedAt:       &now,
+		}
+		if err := tx.Create(ownerMember).Error; err != nil {
+			logs.Error(ctx, funcName, "创建群主成员记录失败", zap.Error(err))
+			return err
+		}
+
+		for _, uid := range memberIDs {
+			member := &imModel.ConversationMember{
+				ConversationID: conv.ID,
+				UserID:         uid,
+				Role:           constants.GroupRoleNormal,
+				JoinedAt:       &now,
+			}
+			if err := tx.Create(member).Error; err != nil {
+				logs.Error(ctx, funcName, "创建群成员记录失败",
+					zap.Int64("user_id", uid), zap.Error(err))
+				return err
+			}
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		logs.Error(ctx, funcName, "创建群聊失败", zap.Error(err))
+		return nil, err
+	}
+	return &group, nil
+}
+
+// GetByID 根据群 ID 获取群信息
+func (d *GroupDAO) GetByID(ctx context.Context, groupID int64) (*model.Group, error) {
+	funcName := "dao.group_dao.GetByID"
+	logs.Debug(ctx, funcName, "获取群信息", zap.Int64("group_id", groupID))
+
+	var group model.Group
+	err := d.db.WithContext(ctx).First(&group, groupID).Error
+	if err != nil {
+		return nil, err
+	}
+	return &group, nil
+}
+
+// GetByConversationID 根据会话 ID 获取群信息
+func (d *GroupDAO) GetByConversationID(ctx context.Context, conversationID int64) (*model.Group, error) {
+	funcName := "dao.group_dao.GetByConversationID"
+	logs.Debug(ctx, funcName, "按会话 ID 获取群信息", zap.Int64("conversation_id", conversationID))
+
+	var group model.Group
+	err := d.db.WithContext(ctx).Where("conversation_id = ?", conversationID).First(&group).Error
+	if err != nil {
+		return nil, err
+	}
+	return &group, nil
+}
+
+// UpdateGroupInfo 更新群基本信息（名称/头像/公告/可搜索性）
+func (d *GroupDAO) UpdateGroupInfo(ctx context.Context, groupID int64, updates map[string]interface{}) error {
+	funcName := "dao.group_dao.UpdateGroupInfo"
+	logs.Info(ctx, funcName, "更新群信息", zap.Int64("group_id", groupID))
+
+	return d.db.WithContext(ctx).
+		Model(&model.Group{}).
+		Where("id = ?", groupID).
+		Updates(updates).Error
+}
+
+// DissolveGroup 解散群聊（标记状态为已解散）
+func (d *GroupDAO) DissolveGroup(ctx context.Context, groupID int64) error {
+	funcName := "dao.group_dao.DissolveGroup"
+	logs.Info(ctx, funcName, "解散群聊", zap.Int64("group_id", groupID))
+
+	return d.db.WithContext(ctx).
+		Model(&model.Group{}).
+		Where("id = ?", groupID).
+		Update("status", constants.GroupStatusDissolved).Error
+}
+
+// TransferOwner 转让群主
+func (d *GroupDAO) TransferOwner(ctx context.Context, groupID, oldOwnerID, newOwnerID int64, conversationID int64) error {
+	funcName := "dao.group_dao.TransferOwner"
+	logs.Info(ctx, funcName, "转让群主",
+		zap.Int64("group_id", groupID), zap.Int64("old_owner", oldOwnerID), zap.Int64("new_owner", newOwnerID))
+
+	return d.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		if err := tx.Model(&model.Group{}).
+			Where("id = ?", groupID).
+			Update("owner_id", newOwnerID).Error; err != nil {
+			return err
+		}
+
+		if err := tx.Model(&imModel.ConversationMember{}).
+			Where("conversation_id = ? AND user_id = ?", conversationID, oldOwnerID).
+			Update("role", constants.GroupRoleNormal).Error; err != nil {
+			return err
+		}
+
+		if err := tx.Model(&imModel.ConversationMember{}).
+			Where("conversation_id = ? AND user_id = ?", conversationID, newOwnerID).
+			Update("role", constants.GroupRoleOwner).Error; err != nil {
+			return err
+		}
+
+		return nil
+	})
+}
+
+// SetAllMuted 设置/取消全体禁言
+func (d *GroupDAO) SetAllMuted(ctx context.Context, groupID int64, isMuted bool) error {
+	funcName := "dao.group_dao.SetAllMuted"
+	logs.Info(ctx, funcName, "设置全体禁言", zap.Int64("group_id", groupID), zap.Bool("is_muted", isMuted))
+
+	return d.db.WithContext(ctx).
+		Model(&model.Group{}).
+		Where("id = ?", groupID).
+		Update("is_all_muted", isMuted).Error
+}
+
+// GetGroupBrief 获取群简要信息（满足 im/service.GroupInfoGetter 接口）
+func (d *GroupDAO) GetGroupBrief(ctx context.Context, conversationID int64) (*dto.GroupBrief, error) {
+	funcName := "dao.group_dao.GetGroupBrief"
+	logs.Debug(ctx, funcName, "获取群简要信息", zap.Int64("conversation_id", conversationID))
+
+	var group model.Group
+	err := d.db.WithContext(ctx).Where("conversation_id = ?", conversationID).First(&group).Error
+	if err != nil {
+		return nil, err
+	}
+	return &dto.GroupBrief{
+		ID:         group.ID,
+		Name:       group.Name,
+		Avatar:     group.Avatar,
+		IsAllMuted: group.IsAllMuted,
+		Status:     group.Status,
+	}, nil
+}
+
+// GetMemberCount 获取群成员数量
+func (d *GroupDAO) GetMemberCount(ctx context.Context, conversationID int64) (int64, error) {
+	var count int64
+	err := d.db.WithContext(ctx).
+		Model(&imModel.ConversationMember{}).
+		Where("conversation_id = ?", conversationID).
+		Count(&count).Error
+	return count, err
+}
+
+// GetMember 获取指定群成员记录
+func (d *GroupDAO) GetMember(ctx context.Context, conversationID, userID int64) (*imModel.ConversationMember, error) {
+	funcName := "dao.group_dao.GetMember"
+	logs.Debug(ctx, funcName, "查询群成员",
+		zap.Int64("conversation_id", conversationID), zap.Int64("user_id", userID))
+
+	var member imModel.ConversationMember
+	err := d.db.WithContext(ctx).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		First(&member).Error
+	if err != nil {
+		return nil, err
+	}
+	return &member, nil
+}
+
+// GetMembers 获取群所有成员列表
+func (d *GroupDAO) GetMembers(ctx context.Context, conversationID int64) ([]imModel.ConversationMember, error) {
+	funcName := "dao.group_dao.GetMembers"
+	logs.Debug(ctx, funcName, "获取群成员列表", zap.Int64("conversation_id", conversationID))
+
+	var members []imModel.ConversationMember
+	err := d.db.WithContext(ctx).
+		Where("conversation_id = ?", conversationID).
+		Order("role DESC, joined_at ASC").
+		Find(&members).Error
+	return members, err
+}
+
+// GetMemberIDs 获取群所有成员 ID
+func (d *GroupDAO) GetMemberIDs(ctx context.Context, conversationID int64) ([]int64, error) {
+	var ids []int64
+	err := d.db.WithContext(ctx).
+		Model(&imModel.ConversationMember{}).
+		Where("conversation_id = ?", conversationID).
+		Pluck("user_id", &ids).Error
+	return ids, err
+}
+
+// GetAdminIDs 获取群主和管理员 ID 列表（用于推送入群申请通知）
+func (d *GroupDAO) GetAdminIDs(ctx context.Context, conversationID int64) ([]int64, error) {
+	var ids []int64
+	err := d.db.WithContext(ctx).
+		Model(&imModel.ConversationMember{}).
+		Where("conversation_id = ? AND role >= ?", conversationID, constants.GroupRoleAdmin).
+		Pluck("user_id", &ids).Error
+	return ids, err
+}
+
+// AddMember 添加群成员
+func (d *GroupDAO) AddMember(ctx context.Context, conversationID, userID int64, role int) error {
+	funcName := "dao.group_dao.AddMember"
+	logs.Info(ctx, funcName, "添加群成员",
+		zap.Int64("conversation_id", conversationID), zap.Int64("user_id", userID))
+
+	now := time.Now()
+	member := &imModel.ConversationMember{
+		ConversationID: conversationID,
+		UserID:         userID,
+		Role:           role,
+		JoinedAt:       &now,
+	}
+	return d.db.WithContext(ctx).Create(member).Error
+}
+
+// RemoveMember 移除群成员
+func (d *GroupDAO) RemoveMember(ctx context.Context, conversationID, userID int64) error {
+	funcName := "dao.group_dao.RemoveMember"
+	logs.Info(ctx, funcName, "移除群成员",
+		zap.Int64("conversation_id", conversationID), zap.Int64("user_id", userID))
+
+	return d.db.WithContext(ctx).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		Delete(&imModel.ConversationMember{}).Error
+}
+
+// UpdateMemberRole 更新成员角色
+func (d *GroupDAO) UpdateMemberRole(ctx context.Context, conversationID, userID int64, role int) error {
+	funcName := "dao.group_dao.UpdateMemberRole"
+	logs.Info(ctx, funcName, "更新成员角色",
+		zap.Int64("conversation_id", conversationID), zap.Int64("user_id", userID), zap.Int("role", role))
+
+	return d.db.WithContext(ctx).
+		Model(&imModel.ConversationMember{}).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		Update("role", role).Error
+}
+
+// UpdateMemberMuted 更新成员禁言状态
+func (d *GroupDAO) UpdateMemberMuted(ctx context.Context, conversationID, userID int64, isMuted bool) error {
+	funcName := "dao.group_dao.UpdateMemberMuted"
+	logs.Info(ctx, funcName, "更新成员禁言状态",
+		zap.Int64("conversation_id", conversationID), zap.Int64("user_id", userID), zap.Bool("is_muted", isMuted))
+
+	return d.db.WithContext(ctx).
+		Model(&imModel.ConversationMember{}).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		Update("is_muted", isMuted).Error
+}
+
+// UpdateMemberNickname 更新成员群内昵称
+func (d *GroupDAO) UpdateMemberNickname(ctx context.Context, conversationID, userID int64, nickname string) error {
+	funcName := "dao.group_dao.UpdateMemberNickname"
+	logs.Info(ctx, funcName, "更新群昵称",
+		zap.Int64("conversation_id", conversationID), zap.Int64("user_id", userID))
+
+	return d.db.WithContext(ctx).
+		Model(&imModel.ConversationMember{}).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		Update("nickname", nickname).Error
+}
+
+// SearchGroups 搜索可发现的群聊（按群名称全文搜索）
+func (d *GroupDAO) SearchGroups(ctx context.Context, keyword string, offset, limit int) ([]model.Group, int64, error) {
+	funcName := "dao.group_dao.SearchGroups"
+	logs.Debug(ctx, funcName, "搜索群聊", zap.String("keyword", keyword))
+
+	var total int64
+	query := d.db.WithContext(ctx).
+		Model(&model.Group{}).
+		Where("status = ? AND is_searchable = true AND to_tsvector('simple', name) @@ plainto_tsquery('simple', ?)",
+			constants.GroupStatusNormal, keyword)
+
+	if err := query.Count(&total).Error; err != nil {
+		logs.Error(ctx, funcName, "搜索计数失败", zap.Error(err))
+		return nil, 0, err
+	}
+
+	var groups []model.Group
+	err := query.Offset(offset).Limit(limit).Order("created_at DESC").Find(&groups).Error
+	if err != nil {
+		logs.Error(ctx, funcName, "搜索查询失败", zap.Error(err))
+		return nil, 0, err
+	}
+	return groups, total, nil
+}
--- a/backend/go-service/app/group/dao/join_request_dao.go
+++ b/backend/go-service/app/group/dao/join_request_dao.go
@@ -0,0 +1,112 @@
+package dao
+
+import (
+	"context"
+
+	"github.com/echochat/backend/app/constants"
+	"github.com/echochat/backend/app/group/model"
+	"github.com/echochat/backend/pkg/logs"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+)
+
+// JoinRequestDAO 入群申请数据访问对象
+type JoinRequestDAO struct {
+	db *gorm.DB
+}
+
+// NewJoinRequestDAO 创建 JoinRequestDAO 实例
+func NewJoinRequestDAO(db *gorm.DB) *JoinRequestDAO {
+	return &JoinRequestDAO{db: db}
+}
+
+// Create 创建入群申请
+func (d *JoinRequestDAO) Create(ctx context.Context, groupID, userID int64, message string) (*model.GroupJoinRequest, error) {
+	funcName := "dao.join_request_dao.Create"
+	logs.Info(ctx, funcName, "创建入群申请",
+		zap.Int64("group_id", groupID), zap.Int64("user_id", userID))
+
+	req := &model.GroupJoinRequest{
+		GroupID: groupID,
+		UserID:  userID,
+		Message: message,
+		Status:  constants.JoinRequestStatusPending,
+	}
+	err := d.db.WithContext(ctx).Create(req).Error
+	if err != nil {
+		logs.Error(ctx, funcName, "创建入群申请失败", zap.Error(err))
+	}
+	return req, err
+}
+
+// GetByID 根据 ID 获取入群申请
+func (d *JoinRequestDAO) GetByID(ctx context.Context, id int64) (*model.GroupJoinRequest, error) {
+	var req model.GroupJoinRequest
+	err := d.db.WithContext(ctx).First(&req, id).Error
+	if err != nil {
+		return nil, err
+	}
+	return &req, nil
+}
+
+// GetPendingByGroupAndUser 查找用户对某群的待处理申请
+func (d *JoinRequestDAO) GetPendingByGroupAndUser(ctx context.Context, groupID, userID int64) (*model.GroupJoinRequest, error) {
+	funcName := "dao.join_request_dao.GetPendingByGroupAndUser"
+	logs.Debug(ctx, funcName, "查找待处理申请",
+		zap.Int64("group_id", groupID), zap.Int64("user_id", userID))
+
+	var req model.GroupJoinRequest
+	err := d.db.WithContext(ctx).
+		Where("group_id = ? AND user_id = ? AND status = ?", groupID, userID, constants.JoinRequestStatusPending).
+		First(&req).Error
+	if err == gorm.ErrRecordNotFound {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &req, nil
+}
+
+// GetListByGroup 获取群的入群申请列表
+func (d *JoinRequestDAO) GetListByGroup(ctx context.Context, groupID int64) ([]model.GroupJoinRequest, error) {
+	funcName := "dao.join_request_dao.GetListByGroup"
+	logs.Debug(ctx, funcName, "获取入群申请列表", zap.Int64("group_id", groupID))
+
+	var requests []model.GroupJoinRequest
+	err := d.db.WithContext(ctx).
+		Where("group_id = ?", groupID).
+		Order("created_at DESC").
+		Find(&requests).Error
+	return requests, err
+}
+
+// Approve 通过入群申请
+func (d *JoinRequestDAO) Approve(ctx context.Context, id, reviewerID int64) error {
+	funcName := "dao.join_request_dao.Approve"
+	logs.Info(ctx, funcName, "通过入群申请",
+		zap.Int64("request_id", id), zap.Int64("reviewer_id", reviewerID))
+
+	return d.db.WithContext(ctx).
+		Model(&model.GroupJoinRequest{}).
+		Where("id = ?", id).
+		Updates(map[string]interface{}{
+			"status":      constants.JoinRequestStatusApproved,
+			"reviewer_id": reviewerID,
+		}).Error
+}
+
+// Reject 拒绝入群申请
+func (d *JoinRequestDAO) Reject(ctx context.Context, id, reviewerID int64) error {
+	funcName := "dao.join_request_dao.Reject"
+	logs.Info(ctx, funcName, "拒绝入群申请",
+		zap.Int64("request_id", id), zap.Int64("reviewer_id", reviewerID))
+
+	return d.db.WithContext(ctx).
+		Model(&model.GroupJoinRequest{}).
+		Where("id = ?", id).
+		Updates(map[string]interface{}{
+			"status":      constants.JoinRequestStatusRejected,
+			"reviewer_id": reviewerID,
+		}).Error
+}
--- a/backend/go-service/app/group/dao/message_read_dao.go
+++ b/backend/go-service/app/group/dao/message_read_dao.go
@@ -0,0 +1,129 @@
+package dao
+
+import (
+	"context"
+
+	"github.com/echochat/backend/app/group/model"
+	"github.com/echochat/backend/pkg/logs"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+)
+
+// MessageReadDAO 消息已读记录数据访问对象
+type MessageReadDAO struct {
+	db *gorm.DB
+}
+
+// NewMessageReadDAO 创建 MessageReadDAO 实例
+func NewMessageReadDAO(db *gorm.DB) *MessageReadDAO {
+	return &MessageReadDAO{db: db}
+}
+
+// BatchCreate 批量创建已读记录（忽略重复冲突）
+func (d *MessageReadDAO) BatchCreate(ctx context.Context, reads []model.MessageRead) error {
+	funcName := "dao.message_read_dao.BatchCreate"
+	logs.Info(ctx, funcName, "批量创建已读记录", zap.Int("count", len(reads)))
+
+	if len(reads) == 0 {
+		return nil
+	}
+	return d.db.WithContext(ctx).
+		Clauses(clause.OnConflict{DoNothing: true}).
+		Create(&reads).Error
+}
+
+// GetReadCount 获取消息的已读人数
+func (d *MessageReadDAO) GetReadCount(ctx context.Context, messageID int64) (int64, error) {
+	var count int64
+	err := d.db.WithContext(ctx).
+		Model(&model.MessageRead{}).
+		Where("message_id = ?", messageID).
+		Count(&count).Error
+	return count, err
+}
+
+// GetReadCountBatch 批量获取多条消息的已读人数
+func (d *MessageReadDAO) GetReadCountBatch(ctx context.Context, messageIDs []int64) (map[int64]int, error) {
+	funcName := "dao.message_read_dao.GetReadCountBatch"
+	logs.Debug(ctx, funcName, "批量获取已读计数", zap.Int("count", len(messageIDs)))
+
+	type result struct {
+		MessageID int64 `gorm:"column:message_id"`
+		ReadCount int   `gorm:"column:read_count"`
+	}
+
+	var results []result
+	err := d.db.WithContext(ctx).
+		Model(&model.MessageRead{}).
+		Select("message_id, COUNT(*) as read_count").
+		Where("message_id IN ?", messageIDs).
+		Group("message_id").
+		Scan(&results).Error
+
+	if err != nil {
+		return nil, err
+	}
+
+	m := make(map[int64]int, len(results))
+	for _, r := range results {
+		m[r.MessageID] = r.ReadCount
+	}
+	return m, nil
+}
+
+// GetReadUsers 获取消息的已读用户列表
+func (d *MessageReadDAO) GetReadUsers(ctx context.Context, messageID int64) ([]model.MessageRead, error) {
+	funcName := "dao.message_read_dao.GetReadUsers"
+	logs.Debug(ctx, funcName, "获取已读用户列表", zap.Int64("message_id", messageID))
+
+	var reads []model.MessageRead
+	err := d.db.WithContext(ctx).
+		Where("message_id = ?", messageID).
+		Order("read_at ASC").
+		Find(&reads).Error
+	return reads, err
+}
+
+// BatchCreateReads 批量标记消息已读（满足 im/service.MessageReadRecorder 接口）
+func (d *MessageReadDAO) BatchCreateReads(ctx context.Context, messageIDs []int64, userID int64) error {
+	funcName := "dao.message_read_dao.BatchCreateReads"
+	logs.Info(ctx, funcName, "批量标记已读",
+		zap.Int64("user_id", userID), zap.Int("count", len(messageIDs)))
+
+	if len(messageIDs) == 0 {
+		return nil
+	}
+
+	reads := make([]model.MessageRead, 0, len(messageIDs))
+	for _, msgID := range messageIDs {
+		reads = append(reads, model.MessageRead{
+			MessageID: msgID,
+			UserID:    userID,
+		})
+	}
+	return d.BatchCreate(ctx, reads)
+}
+
+// GetReadUserIDs 获取消息的已读用户 ID 列表（满足 im/service.MessageReadRecorder 接口）
+func (d *MessageReadDAO) GetReadUserIDs(ctx context.Context, messageID int64) ([]int64, error) {
+	funcName := "dao.message_read_dao.GetReadUserIDs"
+	logs.Debug(ctx, funcName, "获取已读用户 ID 列表", zap.Int64("message_id", messageID))
+
+	var ids []int64
+	err := d.db.WithContext(ctx).
+		Model(&model.MessageRead{}).
+		Where("message_id = ?", messageID).
+		Pluck("user_id", &ids).Error
+	return ids, err
+}
+
+// HasRead 检查用户是否已读某消息
+func (d *MessageReadDAO) HasRead(ctx context.Context, messageID, userID int64) (bool, error) {
+	var count int64
+	err := d.db.WithContext(ctx).
+		Model(&model.MessageRead{}).
+		Where("message_id = ? AND user_id = ?", messageID, userID).
+		Count(&count).Error
+	return count > 0, err
+}
--- a/backend/go-service/app/group/model/group.go
+++ b/backend/go-service/app/group/model/group.go
@@ -0,0 +1,27 @@
+// Package model 定义 group 模块的数据库模型
+package model
+
+import "time"
+
+// Group 群聊信息模型，对应 im_groups 表
+// 与 im_conversations (type=2) 一对一关联
+// Status: 1=正常，2=已解散
+type Group struct {
+	ID             int64     `json:"id" gorm:"primaryKey;autoIncrement"`                          // 群唯一标识
+	ConversationID int64     `json:"conversation_id" gorm:"not null;uniqueIndex"`                 // 关联 im_conversations.id
+	Name           string    `json:"name" gorm:"size:100;not null;default:''"`                    // 群名称
+	Avatar         string    `json:"avatar" gorm:"size:500;default:''"`                           // 群头像 URL（MinIO）
+	OwnerID        int64     `json:"owner_id" gorm:"not null;index:idx_im_groups_owner"`          // 群主用户 ID
+	Notice         string    `json:"notice" gorm:"type:text;default:''"`                          // 群公告内容
+	MaxMembers     int       `json:"max_members" gorm:"not null;default:200"`                     // 最大成员数
+	IsSearchable   bool      `json:"is_searchable" gorm:"not null;default:true"`                  // 是否可被搜索发现
+	IsAllMuted     bool      `json:"is_all_muted" gorm:"not null;default:false"`                  // 是否全体禁言
+	Status         int       `json:"status" gorm:"not null;default:1"`                            // 群状态：1=正常，2=已解散
+	CreatedAt      time.Time `json:"created_at" gorm:"not null;autoCreateTime;type:timestamp(0)"` // 创建时间
+	UpdatedAt      time.Time `json:"updated_at" gorm:"not null;autoUpdateTime;type:timestamp(0)"` // 更新时间
+}
+
+// TableName 指定数据库表名
+func (Group) TableName() string {
+	return "im_groups"
+}
--- a/backend/go-service/app/group/model/join_request.go
+++ b/backend/go-service/app/group/model/join_request.go
@@ -0,0 +1,21 @@
+package model
+
+import "time"
+
+// GroupJoinRequest 入群申请模型，对应 im_group_join_requests 表
+// Status: 0=待审批，1=通过，2=拒绝
+type GroupJoinRequest struct {
+	ID         int64     `json:"id" gorm:"primaryKey;autoIncrement"`                          // 申请唯一标识
+	GroupID    int64     `json:"group_id" gorm:"not null;index:idx_group_join_req_group"`     // 目标群 ID
+	UserID     int64     `json:"user_id" gorm:"not null;index:idx_group_join_req_user"`       // 申请人用户 ID
+	Message    string    `json:"message" gorm:"type:text;default:''"`                         // 申请附言
+	ReviewerID *int64    `json:"reviewer_id"`                                                 // 审批人用户 ID
+	Status     int       `json:"status" gorm:"not null;default:0"`                            // 状态：0=待审批，1=通过，2=拒绝
+	CreatedAt  time.Time `json:"created_at" gorm:"not null;autoCreateTime;type:timestamp(0)"` // 申请时间
+	UpdatedAt  time.Time `json:"updated_at" gorm:"not null;autoUpdateTime;type:timestamp(0)"` // 更新时间
+}
+
+// TableName 指定数据库表名
+func (GroupJoinRequest) TableName() string {
+	return "im_group_join_requests"
+}
--- a/backend/go-service/app/group/model/message_read.go
+++ b/backend/go-service/app/group/model/message_read.go
@@ -0,0 +1,16 @@
+package model
+
+import "time"
+
+// MessageRead 群聊消息已读记录模型，对应 im_message_reads 表
+// 复合主键 (message_id, user_id)，记录每条群消息的已读用户
+type MessageRead struct {
+	MessageID int64     `json:"message_id" gorm:"primaryKey"`                                // 消息 ID
+	UserID    int64     `json:"user_id" gorm:"primaryKey"`                                   // 已读用户 ID
+	ReadAt    time.Time `json:"read_at" gorm:"not null;autoCreateTime;type:timestamp(0)"`    // 已读时间
+}
+
+// TableName 指定数据库表名
+func (MessageRead) TableName() string {
+	return "im_message_reads"
+}
--- a/backend/go-service/app/group/provider.go
+++ b/backend/go-service/app/group/provider.go
@@ -0,0 +1,18 @@
+// Package group 群聊管理模块
+package group
+
+import (
+	"github.com/echochat/backend/app/group/controller"
+	"github.com/echochat/backend/app/group/dao"
+	"github.com/echochat/backend/app/group/service"
+	"github.com/google/wire"
+)
+
+// GroupSet 群聊模块 Wire Provider Set
+var GroupSet = wire.NewSet(
+	dao.NewGroupDAO,
+	dao.NewJoinRequestDAO,
+	dao.NewMessageReadDAO,
+	service.NewGroupService,
+	controller.NewGroupController,
+)
--- a/backend/go-service/app/group/router.go
+++ b/backend/go-service/app/group/router.go
@@ -0,0 +1,38 @@
+package group
+
+import (
+	"github.com/echochat/backend/app/group/controller"
+	"github.com/gin-gonic/gin"
+)
+
+// RegisterRoutes 注册 group 模块的所有路由（需要 JWT 中间件）
+func RegisterRoutes(r *gin.Engine, ctrl *controller.GroupController, jwtAuth gin.HandlerFunc) {
+	authed := r.Group("/api/v1")
+	authed.Use(jwtAuth)
+	{
+		// 群聊管理
+		authed.POST("/groups", ctrl.CreateGroup)
+		authed.GET("/groups/search", ctrl.SearchGroups)
+		authed.GET("/groups/:id", ctrl.GetGroupDetail)
+		authed.PUT("/groups/:id", ctrl.UpdateGroup)
+		authed.DELETE("/groups/:id", ctrl.DissolveGroup)
+
+		// 群成员管理
+		authed.GET("/groups/:id/members", ctrl.GetMembers)
+		authed.POST("/groups/:id/members", ctrl.InviteMembers)
+		authed.DELETE("/groups/:id/members/me", ctrl.LeaveGroup)
+		authed.DELETE("/groups/:id/members/:uid", ctrl.KickMember)
+		authed.PUT("/groups/:id/members/me/nickname", ctrl.UpdateNickname)
+		authed.PUT("/groups/:id/members/:uid/role", ctrl.SetMemberRole)
+		authed.PUT("/groups/:id/members/:uid/mute", ctrl.MuteMember)
+
+		// 群主转让 + 全体禁言
+		authed.PUT("/groups/:id/transfer", ctrl.TransferOwner)
+		authed.PUT("/groups/:id/all-mute", ctrl.SetAllMuted)
+
+		// 入群申请
+		authed.POST("/groups/:id/join-requests", ctrl.SubmitJoinRequest)
+		authed.GET("/groups/:id/join-requests", ctrl.GetJoinRequests)
+		authed.PUT("/groups/:id/join-requests/:rid", ctrl.ReviewJoinRequest)
+	}
+}
--- a/backend/go-service/app/group/service/group_service.go
+++ b/backend/go-service/app/group/service/group_service.go
@@ -0,0 +1,940 @@
+// Package service 提供 group 模块的业务逻辑
+package service
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	authModel "github.com/echochat/backend/app/auth/model"
+	"github.com/echochat/backend/app/constants"
+	"github.com/echochat/backend/app/dto"
+	"github.com/echochat/backend/app/group/dao"
+	"github.com/echochat/backend/app/group/model"
+	imModel "github.com/echochat/backend/app/im/model"
+	"github.com/echochat/backend/pkg/logs"
+	"github.com/echochat/backend/pkg/ws"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+)
+
+var (
+	ErrGroupNotFound        = errors.New("群聊不存在")
+	ErrGroupDissolved       = errors.New("群聊已解散")
+	ErrNotGroupMember       = errors.New("你不是该群成员")
+	ErrNotGroupOwner        = errors.New("仅群主可执行此操作")
+	ErrNotGroupAdmin        = errors.New("仅群主或管理员可执行此操作")
+	ErrGroupFull            = errors.New("群成员已满")
+	ErrAlreadyMember        = errors.New("该用户已是群成员")
+	ErrCannotKickHigherRole = errors.New("不能操作同级或更高权限的成员")
+	ErrOwnerCannotLeave     = errors.New("群主不能退出群聊，请先转让群主")
+	ErrCannotMuteSelf       = errors.New("不能禁言自己")
+	ErrAlreadyMuted         = errors.New("该成员已被禁言")
+	ErrUserMuted            = errors.New("你已被禁言，无法发送消息")
+	ErrGroupAllMuted        = errors.New("当前群已开启全体禁言")
+	ErrPendingRequestExists = errors.New("已有待处理的入群申请")
+	ErrJoinRequestNotFound  = errors.New("入群申请不存在")
+)
+
+// UserInfoProvider 获取用户信息的接口（通过接口注入，由 contact.FriendshipDAO 隐式实现）
+type UserInfoProvider interface {
+	GetUsersByIDs(ctx context.Context, userIDs []int64) ([]authModel.User, error)
+}
+
+// MessageWriter 写入系统消息的接口（由 im.MessageDAO 隐式实现）
+type MessageWriter interface {
+	Create(ctx context.Context, msg *imModel.Message) error
+}
+
+// GroupService 群聊业务服务
+type GroupService struct {
+	groupDAO       *dao.GroupDAO
+	joinRequestDAO *dao.JoinRequestDAO
+	userInfo       UserInfoProvider
+	pubsub         *ws.PubSub
+	msgWriter      MessageWriter
+}
+
+// NewGroupService 创建 GroupService 实例
+func NewGroupService(
+	groupDAO *dao.GroupDAO,
+	joinRequestDAO *dao.JoinRequestDAO,
+	userInfo UserInfoProvider,
+	pubsub *ws.PubSub,
+	msgWriter MessageWriter,
+) *GroupService {
+	return &GroupService{
+		groupDAO:       groupDAO,
+		joinRequestDAO: joinRequestDAO,
+		userInfo:       userInfo,
+		pubsub:         pubsub,
+		msgWriter:      msgWriter,
+	}
+}
+
+// CreateGroup 创建群聊
+func (s *GroupService) CreateGroup(ctx context.Context, ownerID int64, req *dto.CreateGroupRequest) (*dto.GroupDTO, error) {
+	funcName := "service.group_service.CreateGroup"
+	logs.Info(ctx, funcName, "创建群聊",
+		zap.Int64("owner_id", ownerID), zap.String("name", req.Name), zap.Int("member_count", len(req.MemberIDs)))
+
+	group, err := s.groupDAO.CreateGroupWithMembers(ctx, ownerID, req.Name, req.Avatar, req.MemberIDs)
+	if err != nil {
+		logs.Error(ctx, funcName, "创建群聊失败", zap.Error(err))
+		return nil, err
+	}
+
+	s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 创建了群聊", s.getUserNickname(ctx, ownerID)))
+
+	allMemberIDs := append([]int64{ownerID}, req.MemberIDs...)
+	s.pushToMembers(ctx, allMemberIDs, 0, "group.created", map[string]interface{}{
+		"group_id":        group.ID,
+		"conversation_id": group.ConversationID,
+		"name":            group.Name,
+		"owner_id":        ownerID,
+	})
+
+	return s.toGroupDTO(group, int(len(req.MemberIDs)+1)), nil
+}
+
+// GetGroupDetail 获取群详情（需要是群成员）
+func (s *GroupService) GetGroupDetail(ctx context.Context, userID, groupID int64) (*dto.GroupDTO, error) {
+	funcName := "service.group_service.GetGroupDetail"
+	logs.Debug(ctx, funcName, "获取群详情",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, err := s.groupDAO.GetByID(ctx, groupID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrGroupNotFound
+		}
+		return nil, err
+	}
+
+	_, err = s.groupDAO.GetMember(ctx, group.ConversationID, userID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrNotGroupMember
+		}
+		return nil, err
+	}
+
+	count, _ := s.groupDAO.GetMemberCount(ctx, group.ConversationID)
+	return s.toGroupDTO(group, int(count)), nil
+}
+
+// UpdateGroup 更新群信息（群主或管理员）
+func (s *GroupService) UpdateGroup(ctx context.Context, userID, groupID int64, req *dto.UpdateGroupRequest) error {
+	funcName := "service.group_service.UpdateGroup"
+	logs.Info(ctx, funcName, "更新群信息",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, _, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return err
+	}
+
+	updates := make(map[string]interface{})
+	if req.Name != nil {
+		updates["name"] = *req.Name
+	}
+	if req.Avatar != nil {
+		updates["avatar"] = *req.Avatar
+	}
+	if req.Notice != nil {
+		updates["notice"] = *req.Notice
+	}
+	if req.IsSearchable != nil {
+		updates["is_searchable"] = *req.IsSearchable
+	}
+
+	if len(updates) == 0 {
+		return nil
+	}
+
+	if err := s.groupDAO.UpdateGroupInfo(ctx, groupID, updates); err != nil {
+		return err
+	}
+
+	if req.Notice != nil {
+		s.writeSystemMessage(ctx, group.ConversationID,
+			fmt.Sprintf("%s 更新了群公告", s.getUserNickname(ctx, userID)))
+	}
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.info.update", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"operator_id":     userID,
+		"updates":         updates,
+	})
+
+	return nil
+}
+
+// DissolveGroup 解散群聊（仅群主）
+func (s *GroupService) DissolveGroup(ctx context.Context, userID, groupID int64) error {
+	funcName := "service.group_service.DissolveGroup"
+	logs.Info(ctx, funcName, "解散群聊",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return err
+	}
+	if group.OwnerID != userID {
+		return ErrNotGroupOwner
+	}
+
+	memberIDs, _ := s.groupDAO.GetMemberIDs(ctx, group.ConversationID)
+
+	if err := s.groupDAO.DissolveGroup(ctx, groupID); err != nil {
+		return err
+	}
+
+	s.writeSystemMessage(ctx, group.ConversationID, "群聊已解散")
+
+	s.pushToMembers(ctx, memberIDs, 0, "group.dissolved", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"operator_id":     userID,
+	})
+
+	return nil
+}
+
+// GetMembers 获取群成员列表（需要是群成员）
+func (s *GroupService) GetMembers(ctx context.Context, userID, groupID int64) ([]dto.GroupMemberDTO, error) {
+	funcName := "service.group_service.GetMembers"
+	logs.Debug(ctx, funcName, "获取群成员列表",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = s.groupDAO.GetMember(ctx, group.ConversationID, userID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrNotGroupMember
+		}
+		return nil, err
+	}
+
+	members, err := s.groupDAO.GetMembers(ctx, group.ConversationID)
+	if err != nil {
+		return nil, err
+	}
+
+	userIDs := make([]int64, 0, len(members))
+	for _, m := range members {
+		userIDs = append(userIDs, m.UserID)
+	}
+
+	userMap := make(map[int64]*authModel.User)
+	if len(userIDs) > 0 && s.userInfo != nil {
+		users, uErr := s.userInfo.GetUsersByIDs(ctx, userIDs)
+		if uErr != nil {
+			logs.Error(ctx, funcName, "批量查询用户信息失败", zap.Error(uErr))
+		} else {
+			for i := range users {
+				userMap[users[i].ID] = &users[i]
+			}
+		}
+	}
+
+	list := make([]dto.GroupMemberDTO, 0, len(members))
+	for _, m := range members {
+		item := dto.GroupMemberDTO{
+			UserID:   m.UserID,
+			Nickname: m.Nickname,
+			Role:     m.Role,
+			IsMuted:  m.IsMuted,
+		}
+		if m.JoinedAt != nil {
+			item.JoinedAt = m.JoinedAt.Format("2006-01-02 15:04:05")
+		}
+		if user, ok := userMap[m.UserID]; ok {
+			item.UserNickname = user.Nickname
+			item.Avatar = user.Avatar
+		}
+		list = append(list, item)
+	}
+
+	return list, nil
+}
+
+// InviteMembers 邀请用户入群（群主/管理员）
+func (s *GroupService) InviteMembers(ctx context.Context, userID, groupID int64, targetIDs []int64) error {
+	funcName := "service.group_service.InviteMembers"
+	logs.Info(ctx, funcName, "邀请入群",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID), zap.Int("count", len(targetIDs)))
+
+	group, _, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return err
+	}
+
+	count, err := s.groupDAO.GetMemberCount(ctx, group.ConversationID)
+	if err != nil {
+		return err
+	}
+	if int(count)+len(targetIDs) > group.MaxMembers {
+		return ErrGroupFull
+	}
+
+	addedIDs := make([]int64, 0, len(targetIDs))
+	for _, uid := range targetIDs {
+		existing, _ := s.groupDAO.GetMember(ctx, group.ConversationID, uid)
+		if existing != nil {
+			continue
+		}
+		if err := s.groupDAO.AddMember(ctx, group.ConversationID, uid, constants.GroupRoleNormal); err != nil {
+			logs.Error(ctx, funcName, "添加成员失败", zap.Int64("target_id", uid), zap.Error(err))
+			return err
+		}
+		addedIDs = append(addedIDs, uid)
+	}
+
+	if len(addedIDs) > 0 {
+		inviterName := s.getUserNickname(ctx, userID)
+		addedNames := s.getUserNicknames(ctx, addedIDs)
+		s.writeSystemMessage(ctx, group.ConversationID,
+			fmt.Sprintf("%s 邀请 %s 加入了群聊", inviterName, joinNames(addedNames)))
+
+		s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.member.join", map[string]interface{}{
+			"group_id":        groupID,
+			"conversation_id": group.ConversationID,
+			"user_ids":        addedIDs,
+			"operator_id":     userID,
+		})
+	}
+
+	return nil
+}
+
+// KickMember 踢出群成员（群主/管理员，不能操作同级或更高权限的成员）
+func (s *GroupService) KickMember(ctx context.Context, userID, groupID, targetID int64) error {
+	funcName := "service.group_service.KickMember"
+	logs.Info(ctx, funcName, "踢出成员",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID), zap.Int64("target_id", targetID))
+
+	group, operatorMember, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return err
+	}
+
+	targetMember, err := s.groupDAO.GetMember(ctx, group.ConversationID, targetID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrNotGroupMember
+		}
+		return err
+	}
+
+	if targetMember.Role >= operatorMember.Role {
+		return ErrCannotKickHigherRole
+	}
+
+	if err := s.groupDAO.RemoveMember(ctx, group.ConversationID, targetID); err != nil {
+		return err
+	}
+
+	targetName := s.getUserNickname(ctx, targetID)
+	s.writeSystemMessage(ctx, group.ConversationID,
+		fmt.Sprintf("%s 被移出了群聊", targetName))
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.member.kicked", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"user_id":         targetID,
+		"operator_id":     userID,
+	})
+	s.pushToUser(ctx, targetID, "group.member.kicked", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"user_id":         targetID,
+		"operator_id":     userID,
+	})
+
+	return nil
+}
+
+// SetMemberRole 设置/取消管理员（仅群主）
+func (s *GroupService) SetMemberRole(ctx context.Context, userID, groupID, targetID int64, role int) error {
+	funcName := "service.group_service.SetMemberRole"
+	logs.Info(ctx, funcName, "设置成员角色",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID),
+		zap.Int64("target_id", targetID), zap.Int("role", role))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return err
+	}
+	if group.OwnerID != userID {
+		return ErrNotGroupOwner
+	}
+
+	_, err = s.groupDAO.GetMember(ctx, group.ConversationID, targetID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrNotGroupMember
+		}
+		return err
+	}
+
+	if err := s.groupDAO.UpdateMemberRole(ctx, group.ConversationID, targetID, role); err != nil {
+		return err
+	}
+
+	targetName := s.getUserNickname(ctx, targetID)
+	if role == constants.GroupRoleAdmin {
+		s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 被设为管理员", targetName))
+	} else {
+		s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 被取消管理员", targetName))
+	}
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.role.update", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"user_id":         targetID,
+		"role":            role,
+		"operator_id":     userID,
+	})
+
+	return nil
+}
+
+// MuteMember 禁言/解除禁言成员（群主/管理员）
+func (s *GroupService) MuteMember(ctx context.Context, userID, groupID, targetID int64, isMuted bool) error {
+	funcName := "service.group_service.MuteMember"
+	logs.Info(ctx, funcName, "更新禁言状态",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID),
+		zap.Int64("target_id", targetID), zap.Bool("is_muted", isMuted))
+
+	if userID == targetID {
+		return ErrCannotMuteSelf
+	}
+
+	group, operatorMember, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return err
+	}
+
+	targetMember, err := s.groupDAO.GetMember(ctx, group.ConversationID, targetID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrNotGroupMember
+		}
+		return err
+	}
+
+	if targetMember.Role >= operatorMember.Role {
+		return ErrCannotKickHigherRole
+	}
+
+	if err := s.groupDAO.UpdateMemberMuted(ctx, group.ConversationID, targetID, isMuted); err != nil {
+		return err
+	}
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.mute.update", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"user_id":         targetID,
+		"is_muted":        isMuted,
+		"operator_id":     userID,
+	})
+
+	return nil
+}
+
+// LeaveGroup 退出群聊（群主不能退出，需先转让）
+func (s *GroupService) LeaveGroup(ctx context.Context, userID, groupID int64) error {
+	funcName := "service.group_service.LeaveGroup"
+	logs.Info(ctx, funcName, "退出群聊",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return err
+	}
+	if group.OwnerID == userID {
+		return ErrOwnerCannotLeave
+	}
+
+	_, err = s.groupDAO.GetMember(ctx, group.ConversationID, userID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrNotGroupMember
+		}
+		return err
+	}
+
+	if err := s.groupDAO.RemoveMember(ctx, group.ConversationID, userID); err != nil {
+		return err
+	}
+
+	userName := s.getUserNickname(ctx, userID)
+	s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 退出了群聊", userName))
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.member.leave", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"user_id":         userID,
+	})
+
+	return nil
+}
+
+// TransferOwner 转让群主（仅群主）
+func (s *GroupService) TransferOwner(ctx context.Context, userID, groupID, newOwnerID int64) error {
+	funcName := "service.group_service.TransferOwner"
+	logs.Info(ctx, funcName, "转让群主",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID), zap.Int64("new_owner", newOwnerID))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return err
+	}
+	if group.OwnerID != userID {
+		return ErrNotGroupOwner
+	}
+
+	_, err = s.groupDAO.GetMember(ctx, group.ConversationID, newOwnerID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrNotGroupMember
+		}
+		return err
+	}
+
+	if err := s.groupDAO.TransferOwner(ctx, groupID, userID, newOwnerID, group.ConversationID); err != nil {
+		return err
+	}
+
+	oldOwnerName := s.getUserNickname(ctx, userID)
+	newOwnerName := s.getUserNickname(ctx, newOwnerID)
+	s.writeSystemMessage(ctx, group.ConversationID,
+		fmt.Sprintf("%s 将群主转让给了 %s", oldOwnerName, newOwnerName))
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.owner.transfer", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"old_owner_id":    userID,
+		"new_owner_id":    newOwnerID,
+	})
+
+	return nil
+}
+
+// UpdateNickname 修改群内昵称
+func (s *GroupService) UpdateNickname(ctx context.Context, userID, groupID int64, nickname string) error {
+	funcName := "service.group_service.UpdateNickname"
+	logs.Info(ctx, funcName, "修改群昵称",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return err
+	}
+
+	_, err = s.groupDAO.GetMember(ctx, group.ConversationID, userID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrNotGroupMember
+		}
+		return err
+	}
+
+	return s.groupDAO.UpdateMemberNickname(ctx, group.ConversationID, userID, nickname)
+}
+
+// SubmitJoinRequest 提交入群申请
+func (s *GroupService) SubmitJoinRequest(ctx context.Context, userID, groupID int64, message string) error {
+	funcName := "service.group_service.SubmitJoinRequest"
+	logs.Info(ctx, funcName, "提交入群申请",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return err
+	}
+
+	existing, _ := s.groupDAO.GetMember(ctx, group.ConversationID, userID)
+	if existing != nil {
+		return ErrAlreadyMember
+	}
+
+	pending, _ := s.joinRequestDAO.GetPendingByGroupAndUser(ctx, groupID, userID)
+	if pending != nil {
+		return ErrPendingRequestExists
+	}
+
+	req, err := s.joinRequestDAO.Create(ctx, groupID, userID, message)
+	if err != nil {
+		return err
+	}
+
+	adminIDs, _ := s.groupDAO.GetAdminIDs(ctx, group.ConversationID)
+	userName := s.getUserNickname(ctx, userID)
+	s.pushToMembers(ctx, adminIDs, 0, "group.join.request", map[string]interface{}{
+		"group_id":      groupID,
+		"request_id":    req.ID,
+		"user_id":       userID,
+		"user_nickname": userName,
+		"message":       message,
+	})
+
+	return nil
+}
+
+// GetJoinRequests 获取入群申请列表（群主/管理员）
+func (s *GroupService) GetJoinRequests(ctx context.Context, userID, groupID int64) ([]dto.JoinRequestDTO, error) {
+	funcName := "service.group_service.GetJoinRequests"
+	logs.Debug(ctx, funcName, "获取入群申请列表",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID))
+
+	_, _, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return nil, err
+	}
+
+	requests, err := s.joinRequestDAO.GetListByGroup(ctx, groupID)
+	if err != nil {
+		return nil, err
+	}
+
+	userIDs := make([]int64, 0, len(requests))
+	for _, r := range requests {
+		userIDs = append(userIDs, r.UserID)
+	}
+
+	userMap := make(map[int64]*authModel.User)
+	if len(userIDs) > 0 && s.userInfo != nil {
+		users, uErr := s.userInfo.GetUsersByIDs(ctx, userIDs)
+		if uErr != nil {
+			logs.Error(ctx, funcName, "批量查询用户信息失败", zap.Error(uErr))
+		} else {
+			for i := range users {
+				userMap[users[i].ID] = &users[i]
+			}
+		}
+	}
+
+	list := make([]dto.JoinRequestDTO, 0, len(requests))
+	for _, r := range requests {
+		item := dto.JoinRequestDTO{
+			ID:        r.ID,
+			GroupID:   r.GroupID,
+			UserID:    r.UserID,
+			Message:   r.Message,
+			Status:    r.Status,
+			CreatedAt: r.CreatedAt.Format("2006-01-02 15:04:05"),
+		}
+		if user, ok := userMap[r.UserID]; ok {
+			item.UserNickname = user.Nickname
+			item.UserAvatar = user.Avatar
+		}
+		list = append(list, item)
+	}
+
+	return list, nil
+}
+
+// ReviewJoinRequest 审批入群申请（群主/管理员）
+func (s *GroupService) ReviewJoinRequest(ctx context.Context, userID, groupID, requestID int64, action string) error {
+	funcName := "service.group_service.ReviewJoinRequest"
+	logs.Info(ctx, funcName, "审批入群申请",
+		zap.Int64("user_id", userID), zap.Int64("request_id", requestID), zap.String("action", action))
+
+	group, _, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return err
+	}
+
+	req, err := s.joinRequestDAO.GetByID(ctx, requestID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return ErrJoinRequestNotFound
+		}
+		return err
+	}
+
+	if req.GroupID != groupID || req.Status != constants.JoinRequestStatusPending {
+		return ErrJoinRequestNotFound
+	}
+
+	if action == "approve" {
+		count, _ := s.groupDAO.GetMemberCount(ctx, group.ConversationID)
+		if int(count) >= group.MaxMembers {
+			return ErrGroupFull
+		}
+
+		if err := s.joinRequestDAO.Approve(ctx, requestID, userID); err != nil {
+			return err
+		}
+		if err := s.groupDAO.AddMember(ctx, group.ConversationID, req.UserID, constants.GroupRoleNormal); err != nil {
+			return err
+		}
+
+		newMemberName := s.getUserNickname(ctx, req.UserID)
+		s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 加入了群聊", newMemberName))
+
+		s.pushToUser(ctx, req.UserID, "group.join.approved", map[string]interface{}{
+			"group_id":        groupID,
+			"conversation_id": group.ConversationID,
+			"request_id":      requestID,
+		})
+
+		s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.member.join", map[string]interface{}{
+			"group_id":        groupID,
+			"conversation_id": group.ConversationID,
+			"user_ids":        []int64{req.UserID},
+		})
+
+		return nil
+	}
+
+	return s.joinRequestDAO.Reject(ctx, requestID, userID)
+}
+
+// SearchGroups 搜索公开群
+func (s *GroupService) SearchGroups(ctx context.Context, req *dto.SearchGroupRequest) (*dto.SearchGroupResponse, error) {
+	funcName := "service.group_service.SearchGroups"
+	logs.Debug(ctx, funcName, "搜索群聊", zap.String("keyword", req.Keyword))
+
+	page := req.Page
+	if page <= 0 {
+		page = 1
+	}
+	pageSize := req.PageSize
+	if pageSize <= 0 {
+		pageSize = 20
+	}
+	offset := (page - 1) * pageSize
+
+	groups, total, err := s.groupDAO.SearchGroups(ctx, req.Keyword, offset, pageSize)
+	if err != nil {
+		return nil, err
+	}
+
+	list := make([]dto.GroupDTO, 0, len(groups))
+	for _, g := range groups {
+		count, _ := s.groupDAO.GetMemberCount(ctx, g.ConversationID)
+		list = append(list, *s.toGroupDTO(&g, int(count)))
+	}
+
+	return &dto.SearchGroupResponse{List: list, Total: total}, nil
+}
+
+// SetAllMuted 设置/取消全体禁言（群主/管理员）
+func (s *GroupService) SetAllMuted(ctx context.Context, userID, groupID int64, isMuted bool) error {
+	funcName := "service.group_service.SetAllMuted"
+	logs.Info(ctx, funcName, "设置全体禁言",
+		zap.Int64("user_id", userID), zap.Int64("group_id", groupID), zap.Bool("is_muted", isMuted))
+
+	group, _, err := s.checkGroupAdmin(ctx, groupID, userID)
+	if err != nil {
+		return err
+	}
+
+	if err := s.groupDAO.SetAllMuted(ctx, groupID, isMuted); err != nil {
+		return err
+	}
+
+	operatorName := s.getUserNickname(ctx, userID)
+	if isMuted {
+		s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 开启了全体禁言", operatorName))
+	} else {
+		s.writeSystemMessage(ctx, group.ConversationID, fmt.Sprintf("%s 关闭了全体禁言", operatorName))
+	}
+
+	s.pushToGroupMembers(ctx, group.ConversationID, 0, "group.mute.update", map[string]interface{}{
+		"group_id":        groupID,
+		"conversation_id": group.ConversationID,
+		"is_all_muted":    isMuted,
+		"operator_id":     userID,
+	})
+
+	return nil
+}
+
+// ====== 内部辅助方法 ======
+
+// getActiveGroup 获取群聊并校验是否存在且未解散
+func (s *GroupService) getActiveGroup(ctx context.Context, groupID int64) (*model.Group, error) {
+	group, err := s.groupDAO.GetByID(ctx, groupID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrGroupNotFound
+		}
+		return nil, err
+	}
+	if group.Status == constants.GroupStatusDissolved {
+		return nil, ErrGroupDissolved
+	}
+	return group, nil
+}
+
+// checkGroupAdmin 校验用户是群主或管理员
+func (s *GroupService) checkGroupAdmin(ctx context.Context, groupID, userID int64) (*model.Group, *imMember, error) {
+	group, err := s.getActiveGroup(ctx, groupID)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	member, err := s.groupDAO.GetMember(ctx, group.ConversationID, userID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, nil, ErrNotGroupMember
+		}
+		return nil, nil, err
+	}
+
+	if member.Role < constants.GroupRoleAdmin {
+		return nil, nil, ErrNotGroupAdmin
+	}
+
+	return group, &imMember{
+		UserID: member.UserID,
+		Role:   member.Role,
+	}, nil
+}
+
+// imMember 内部使用的成员简要信息
+type imMember struct {
+	UserID int64
+	Role   int
+}
+
+// ====== 推送和系统消息辅助方法 ======
+
+// pushToUser 向单个用户推送通知
+func (s *GroupService) pushToUser(ctx context.Context, userID int64, event string, data interface{}) {
+	if s.pubsub == nil {
+		return
+	}
+	push := ws.NewPushMessage(event, data)
+	bytes, err := ws.MarshalPush(push)
+	if err != nil {
+		logs.Error(ctx, "service.group_service.pushToUser", "序列化推送消息失败", zap.Error(err))
+		return
+	}
+	if err := s.pubsub.Publish(ctx, userID, bytes); err != nil {
+		logs.Error(ctx, "service.group_service.pushToUser", "推送失败",
+			zap.Int64("user_id", userID), zap.Error(err))
+	}
+}
+
+// pushToMembers 向指定用户列表推送通知（排除 excludeUID）
+func (s *GroupService) pushToMembers(ctx context.Context, memberIDs []int64, excludeUID int64, event string, data interface{}) {
+	if s.pubsub == nil || len(memberIDs) == 0 {
+		return
+	}
+	push := ws.NewPushMessage(event, data)
+	bytes, err := ws.MarshalPush(push)
+	if err != nil {
+		logs.Error(ctx, "service.group_service.pushToMembers", "序列化推送消息失败", zap.Error(err))
+		return
+	}
+	for _, uid := range memberIDs {
+		if uid == excludeUID {
+			continue
+		}
+		if pErr := s.pubsub.Publish(ctx, uid, bytes); pErr != nil {
+			logs.Error(ctx, "service.group_service.pushToMembers", "推送失败",
+				zap.Int64("user_id", uid), zap.Error(pErr))
+		}
+	}
+}
+
+// pushToGroupMembers 向群所有成员推送通知（通过 conversationID 查成员）
+func (s *GroupService) pushToGroupMembers(ctx context.Context, conversationID int64, excludeUID int64, event string, data interface{}) {
+	memberIDs, err := s.groupDAO.GetMemberIDs(ctx, conversationID)
+	if err != nil {
+		logs.Error(ctx, "service.group_service.pushToGroupMembers", "获取成员列表失败", zap.Error(err))
+		return
+	}
+	s.pushToMembers(ctx, memberIDs, excludeUID, event, data)
+}
+
+// writeSystemMessage 写入系统消息到群会话
+func (s *GroupService) writeSystemMessage(ctx context.Context, conversationID int64, content string) {
+	if s.msgWriter == nil {
+		return
+	}
+	msg := &imModel.Message{
+		ConversationID: conversationID,
+		SenderID:       0,
+		Type:           constants.MessageTypeSystem,
+		Content:        content,
+		Status:         constants.MessageStatusNormal,
+	}
+	if err := s.msgWriter.Create(ctx, msg); err != nil {
+		logs.Error(ctx, "service.group_service.writeSystemMessage", "写入系统消息失败", zap.Error(err))
+	}
+}
+
+// getUserNickname 获取单个用户昵称（推送文案使用，查询失败返回默认值）
+func (s *GroupService) getUserNickname(ctx context.Context, userID int64) string {
+	if s.userInfo == nil {
+		return "用户"
+	}
+	users, err := s.userInfo.GetUsersByIDs(ctx, []int64{userID})
+	if err != nil || len(users) == 0 {
+		return "用户"
+	}
+	return users[0].Nickname
+}
+
+// getUserNicknames 批量获取用户昵称列表
+func (s *GroupService) getUserNicknames(ctx context.Context, userIDs []int64) []string {
+	if s.userInfo == nil || len(userIDs) == 0 {
+		return nil
+	}
+	users, err := s.userInfo.GetUsersByIDs(ctx, userIDs)
+	if err != nil {
+		return nil
+	}
+	nameMap := make(map[int64]string, len(users))
+	for _, u := range users {
+		nameMap[u.ID] = u.Nickname
+	}
+	names := make([]string, 0, len(userIDs))
+	for _, id := range userIDs {
+		if n, ok := nameMap[id]; ok {
+			names = append(names, n)
+		}
+	}
+	return names
+}
+
+// joinNames 将名称列表用顿号连接（中文习惯）
+func joinNames(names []string) string {
+	if len(names) == 0 {
+		return ""
+	}
+	result := names[0]
+	for i := 1; i < len(names); i++ {
+		result += "、" + names[i]
+	}
+	return result
+}
+
+// toGroupDTO 将 model.Group 转换为 dto.GroupDTO
+func (s *GroupService) toGroupDTO(g *model.Group, memberCount int) *dto.GroupDTO {
+	return &dto.GroupDTO{
+		ID:             g.ID,
+		ConversationID: g.ConversationID,
+		Name:           g.Name,
+		Avatar:         g.Avatar,
+		OwnerID:        g.OwnerID,
+		Notice:         g.Notice,
+		MaxMembers:     g.MaxMembers,
+		MemberCount:    memberCount,
+		IsSearchable:   g.IsSearchable,
+		IsAllMuted:     g.IsAllMuted,
+		Status:         g.Status,
+		CreatedAt:      g.CreatedAt.Format("2006-01-02 15:04:05"),
+	}
+}
--- a/backend/go-service/app/im/controller/im_controller.go
+++ b/backend/go-service/app/im/controller/im_controller.go
@@ -180,6 +180,30 @@ func (ctl *IMController) GetTotalUnread(c *gin.Context) {
 	utils.ResponseOK(c, gin.H{"total_unread": count})
 }

+// GetMessageReadDetail 获取消息已读详情
+// GET /api/v1/im/messages/:id/reads
+func (ctl *IMController) GetMessageReadDetail(c *gin.Context) {
+	ctx := c.Request.Context()
+	userID, ok := middleware.GetCurrentUserID(c)
+	if !ok {
+		utils.ResponseUnauthorized(c, "无法获取当前用户信息")
+		return
+	}
+
+	messageID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		utils.ResponseBadRequest(c, "消息 ID 格式错误")
+		return
+	}
+
+	result, err := ctl.imService.GetMessageReadDetail(ctx, userID, messageID)
+	if err != nil {
+		ctl.handleError(c, err, "获取已读详情失败")
+		return
+	}
+	utils.ResponseOK(c, result)
+}
+
 // handleError 统一业务错误映射
 // 已知业务错误 → 返回 Service 层定义的具体提示
 // 未知错误 → 返回 fallbackMsg（未传则默认"服务器内部错误"）
@@ -203,6 +227,12 @@ func (ctl *IMController) handleError(c *gin.Context, err error, fallbackMsg ...s
 		utils.ResponseForbidden(c, err.Error())
 	case service.ErrDuplicateMsg:
 		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrGroupDissolved:
+		utils.ResponseBadRequest(c, err.Error())
+	case service.ErrGroupAllMuted:
+		utils.ResponseForbidden(c, err.Error())
+	case service.ErrUserMuted:
+		utils.ResponseForbidden(c, err.Error())
 	default:
 		msg := "服务器内部错误"
 		if len(fallbackMsg) > 0 && fallbackMsg[0] != "" {
--- a/backend/go-service/app/im/dao/conversation_dao.go
+++ b/backend/go-service/app/im/dao/conversation_dao.go
@@ -86,13 +86,14 @@ func (d *ConversationDAO) GetUserConversations(ctx context.Context, userID int64
 	err := d.db.WithContext(ctx).
 		Raw(`SELECT c.id, c.type, c.last_message_id, c.last_msg_content, c.last_msg_time, c.last_msg_sender_id,
 			        cm.is_pinned, cm.unread_count, cm.clear_before_msg_id,
-			        peer.user_id AS peer_user_id
+			        cm.is_do_not_disturb, cm.at_me_count,
+			        COALESCE(peer.user_id, 0) AS peer_user_id
 			 FROM im_conversations c
 			 JOIN im_conversation_members cm ON cm.conversation_id = c.id AND cm.user_id = ?
-			 LEFT JOIN im_conversation_members peer ON peer.conversation_id = c.id AND peer.user_id != ?
+			 LEFT JOIN im_conversation_members peer ON peer.conversation_id = c.id AND peer.user_id != ? AND c.type = ?
 			 WHERE cm.is_deleted = false
 			 ORDER BY cm.is_pinned DESC, c.last_msg_time DESC NULLS LAST`,
-			userID, userID).
+			userID, userID, constants.ConversationTypePrivate).
 		Scan(&results).Error

 	if err != nil {
@@ -112,6 +113,8 @@ type ConversationWithMember struct {
 	IsPinned         bool       `json:"is_pinned"`
 	UnreadCount      int        `json:"unread_count"`
 	ClearBeforeMsgID int64      `json:"clear_before_msg_id"`
+	IsDoNotDisturb   bool       `json:"is_do_not_disturb"`
+	AtMeCount        int        `json:"at_me_count"`
 	PeerUserID       int64      `json:"peer_user_id"`
 }

@@ -216,6 +219,44 @@ func (d *ConversationDAO) IncrementUnread(ctx context.Context, conversationID, u
 		UpdateColumn("unread_count", gorm.Expr("unread_count + 1")).Error
 }

+// IncrementAtMeCount 将指定成员的 @提醒计数 +1
+func (d *ConversationDAO) IncrementAtMeCount(ctx context.Context, conversationID, userID int64) error {
+	return d.db.WithContext(ctx).
+		Model(&model.ConversationMember{}).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		UpdateColumn("at_me_count", gorm.Expr("at_me_count + 1")).Error
+}
+
+// ClearAtMeCount 清零指定成员的 @提醒计数
+func (d *ConversationDAO) ClearAtMeCount(ctx context.Context, conversationID, userID int64) error {
+	return d.db.WithContext(ctx).
+		Model(&model.ConversationMember{}).
+		Where("conversation_id = ? AND user_id = ?", conversationID, userID).
+		Update("at_me_count", 0).Error
+}
+
+// GetMemberDNDMap 批量获取会话成员的免打扰状态（返回 userID → isDoNotDisturb 的映射）
+func (d *ConversationDAO) GetMemberDNDMap(ctx context.Context, conversationID int64) (map[int64]bool, error) {
+	type memberDND struct {
+		UserID         int64 `json:"user_id"`
+		IsDoNotDisturb bool  `json:"is_do_not_disturb"`
+	}
+	var members []memberDND
+	err := d.db.WithContext(ctx).
+		Model(&model.ConversationMember{}).
+		Select("user_id, is_do_not_disturb").
+		Where("conversation_id = ?", conversationID).
+		Scan(&members).Error
+	if err != nil {
+		return nil, err
+	}
+	result := make(map[int64]bool, len(members))
+	for _, m := range members {
+		result[m.UserID] = m.IsDoNotDisturb
+	}
+	return result, nil
+}
+
 // ClearUnread 清零指定成员的未读消息数
 func (d *ConversationDAO) ClearUnread(ctx context.Context, conversationID, userID int64, lastMsgID int64) error {
 	return d.db.WithContext(ctx).
--- a/backend/go-service/app/im/handler/event_handler.go
+++ b/backend/go-service/app/im/handler/event_handler.go
@@ -34,6 +34,7 @@ func (h *EventHandler) registerEvents() {
 	h.hub.RegisterEvent("im.message.send", h.handleSendMessage)
 	h.hub.RegisterEvent("im.message.recall", h.handleRecallMessage)
 	h.hub.RegisterEvent("im.conversation.read", h.handleMarkRead)
+	h.hub.RegisterEvent("im.group.read", h.handleGroupRead)
 	h.hub.RegisterEvent("im.typing", h.handleTyping)
 }

@@ -111,6 +112,29 @@ func (h *EventHandler) handleMarkRead(client *ws.Client, msg *ws.Message) {
 	h.sendACK(client, msg, 0, "ok", nil)
 }

+// handleGroupRead 处理群聊消息标记已读事件
+func (h *EventHandler) handleGroupRead(client *ws.Client, msg *ws.Message) {
+	funcName := "handler.event_handler.handleGroupRead"
+	ctx := context.Background()
+
+	var req dto.MarkGroupReadRequest
+	if err := json.Unmarshal(msg.Data, &req); err != nil {
+		logs.Warn(ctx, funcName, "解析群已读请求失败",
+			zap.Int64("user_id", client.UserID), zap.Error(err))
+		h.sendACK(client, msg, -1, "请求参数格式错误", nil)
+		return
+	}
+
+	if err := h.imService.MarkGroupMessagesRead(ctx, client.UserID, &req); err != nil {
+		logs.Warn(ctx, funcName, "群已读标记失败",
+			zap.Int64("user_id", client.UserID), zap.Error(err))
+		h.sendACK(client, msg, -1, err.Error(), nil)
+		return
+	}
+
+	h.sendACK(client, msg, 0, "ok", nil)
+}
+
 // handleTyping 处理正在输入事件（通过 PubSub 转发给对方，支持跨实例）
 func (h *EventHandler) handleTyping(client *ws.Client, msg *ws.Message) {
 	funcName := "handler.event_handler.handleTyping"
--- a/backend/go-service/app/im/model/conversation_member.go
+++ b/backend/go-service/app/im/model/conversation_member.go
@@ -4,17 +4,24 @@ import "time"

 // ConversationMember 会话成员模型，对应 im_conversation_members 表
 // 每个会话的每个成员一条记录，存储置顶/未读/软删除等个人视图
+// 群聊场景下额外使用 Role/Nickname/IsMuted/IsDoNotDisturb/JoinedAt/AtMeCount 字段
 type ConversationMember struct {
-	ID             int64     `json:"id" gorm:"primaryKey;autoIncrement"`                          // 记录唯一标识
-	ConversationID int64     `json:"conversation_id" gorm:"not null;uniqueIndex:idx_conv_user"`   // 所属会话 ID
-	UserID         int64     `json:"user_id" gorm:"not null;uniqueIndex:idx_conv_user"`           // 成员用户 ID
-	IsPinned       bool      `json:"is_pinned" gorm:"default:false"`                              // 是否置顶该会话
-	IsDeleted      bool      `json:"is_deleted" gorm:"default:false"`                             // 是否删除该会话（软删除，不影响对方）
-	UnreadCount    int       `json:"unread_count" gorm:"default:0"`                               // 该成员在此会话中的未读消息数
-	LastReadMsgID    int64     `json:"last_read_msg_id" gorm:"default:0"`                           // 该成员最后已读消息 ID
-	ClearBeforeMsgID int64     `json:"clear_before_msg_id" gorm:"default:0"`                       // 清空记录时的消息截止 ID（个人视图，不影响对方）
-	CreatedAt        time.Time `json:"created_at" gorm:"not null;autoCreateTime;type:timestamp(0)"` // 加入会话时间
-	UpdatedAt      time.Time `json:"updated_at" gorm:"not null;autoUpdateTime;type:timestamp(0)"` // 最后更新时间
+	ID               int64      `json:"id" gorm:"primaryKey;autoIncrement"`                          // 记录唯一标识
+	ConversationID   int64      `json:"conversation_id" gorm:"not null;uniqueIndex:idx_conv_user"`   // 所属会话 ID
+	UserID           int64      `json:"user_id" gorm:"not null;uniqueIndex:idx_conv_user"`           // 成员用户 ID
+	IsPinned         bool       `json:"is_pinned" gorm:"default:false"`                              // 是否置顶该会话
+	IsDeleted        bool       `json:"is_deleted" gorm:"default:false"`                             // 是否删除该会话（软删除，不影响对方）
+	UnreadCount      int        `json:"unread_count" gorm:"default:0"`                               // 该成员在此会话中的未读消息数
+	LastReadMsgID    int64      `json:"last_read_msg_id" gorm:"default:0"`                           // 该成员最后已读消息 ID
+	ClearBeforeMsgID int64      `json:"clear_before_msg_id" gorm:"default:0"`                        // 清空记录时的消息截止 ID（个人视图，不影响对方）
+	Role             int        `json:"role" gorm:"not null;default:0"`                              // 成员角色：0=普通成员，1=管理员，2=群主
+	Nickname         string     `json:"nickname" gorm:"size:50;default:''"`                          // 群内昵称（仅群聊有效）
+	IsMuted          bool       `json:"is_muted" gorm:"not null;default:false"`                      // 是否被禁言
+	IsDoNotDisturb   bool       `json:"is_do_not_disturb" gorm:"not null;default:false"`             // 是否消息免打扰
+	JoinedAt         *time.Time `json:"joined_at" gorm:"type:timestamp(0)"`                          // 加入群聊时间
+	AtMeCount        int        `json:"at_me_count" gorm:"default:0"`                                // 被@提醒未读计数
+	CreatedAt        time.Time  `json:"created_at" gorm:"not null;autoCreateTime;type:timestamp(0)"` // 加入会话时间
+	UpdatedAt        time.Time  `json:"updated_at" gorm:"not null;autoUpdateTime;type:timestamp(0)"` // 最后更新时间
 }

 // TableName 指定数据库表名
--- a/backend/go-service/app/im/model/message.go
+++ b/backend/go-service/app/im/model/message.go
@@ -1,20 +1,25 @@
 package model

-import "time"
+import (
+	"time"
+
+	"github.com/echochat/backend/pkg/utils"
+)

 // Message 消息模型，对应 im_messages 表
-// Type: 1=文本（预留 2=图片 3=语音 4=视频 5=文件）
+// Type: 1=文本（预留 2=图片 3=语音 4=视频 5=文件），10=系统消息
 // Status: 1=正常 2=已撤回 3=已删除
 type Message struct {
-	ID             int64     `json:"id" gorm:"primaryKey;autoIncrement"`                                       // 消息唯一标识，自增主键
-	ConversationID int64     `json:"conversation_id" gorm:"not null;index:idx_msg_conv_time;index:idx_msg_conv_id"` // 所属会话 ID
-	SenderID       int64     `json:"sender_id" gorm:"not null"`                                                // 发送者用户 ID
-	Type           int       `json:"type" gorm:"not null;default:1"`                                           // 消息类型：1=文本（预留扩展）
-	Content        string    `json:"content" gorm:"type:text;not null"`                                        // 消息内容
-	Extra          *string   `json:"extra" gorm:"type:jsonb"`                                                  // 扩展数据（JSON 格式，预留图片/语音等元信息）
-	Status         int       `json:"status" gorm:"not null;default:1"`                                         // 消息状态：1=正常，2=已撤回，3=已删除
-	ClientMsgID    string    `json:"client_msg_id" gorm:"size:64;default:''"`                                  // 客户端消息唯一 ID，用于幂等去重
-	CreatedAt      time.Time `json:"created_at" gorm:"not null;autoCreateTime;type:timestamp(0)"`              // 消息发送时间
+	ID             int64            `json:"id" gorm:"primaryKey;autoIncrement"`                                       // 消息唯一标识，自增主键
+	ConversationID int64            `json:"conversation_id" gorm:"not null;index:idx_msg_conv_time;index:idx_msg_conv_id"` // 所属会话 ID
+	SenderID       int64            `json:"sender_id" gorm:"not null"`                                                // 发送者用户 ID（系统消息为 0）
+	Type           int              `json:"type" gorm:"not null;default:1"`                                           // 消息类型：1=文本，10=系统消息
+	Content        string           `json:"content" gorm:"type:text;not null"`                                        // 消息内容
+	Extra          *string          `json:"extra" gorm:"type:jsonb"`                                                  // 扩展数据（JSON 格式，预留图片/语音等元信息）
+	Status         int              `json:"status" gorm:"not null;default:1"`                                         // 消息状态：1=正常，2=已撤回，3=已删除
+	ClientMsgID    string           `json:"client_msg_id" gorm:"size:64;default:''"`                                  // 客户端消息唯一 ID，用于幂等去重
+	AtUserIDs      utils.Int64Array `json:"at_user_ids" gorm:"type:bigint[]"`                                         // @提醒用户 ID 列表，nil=无@，含 0 表示 @所有人
+	CreatedAt      time.Time        `json:"created_at" gorm:"not null;autoCreateTime;type:timestamp(0)"`              // 消息发送时间
 }

 // TableName 指定数据库表名
--- a/backend/go-service/app/im/provider.go
+++ b/backend/go-service/app/im/provider.go
@@ -22,7 +22,8 @@ func ProvideMessageDAO(db *gorm.DB) *dao.MessageDAO {
 }

 // ProvideIMService 创建 IMService 实例
-// friendChecker 和 userInfoGetter 由 contact 模块的 FriendshipDAO 隐式实现
+// friendChecker / userInfoGetter 由 contact.FriendshipDAO 隐式实现
+// groupInfo 由 group.GroupDAO 隐式实现
 func ProvideIMService(
 	convDAO *dao.ConversationDAO,
 	msgDAO *dao.MessageDAO,
@@ -30,8 +31,10 @@ func ProvideIMService(
 	rdb *redis.Client,
 	friendChecker service.FriendChecker,
 	userInfoGetter service.UserInfoGetter,
+	groupInfo service.GroupInfoGetter,
+	readRecorder service.MessageReadRecorder,
 ) *service.IMService {
-	return service.NewIMService(convDAO, msgDAO, pubsub, rdb, friendChecker, userInfoGetter)
+	return service.NewIMService(convDAO, msgDAO, pubsub, rdb, friendChecker, userInfoGetter, groupInfo, readRecorder)
 }

 // ProvideIMEventHandler 创建 IM WS 事件处理器并注册事件到 Hub
--- a/backend/go-service/app/im/router.go
+++ b/backend/go-service/app/im/router.go
@@ -23,5 +23,8 @@ func RegisterRoutes(r *gin.Engine, ctrl *controller.IMController, jwtAuth gin.Ha

 		// 未读数
 		authed.GET("/unread", ctrl.GetTotalUnread)
+
+		// 已读回执
+		authed.GET("/messages/:id/reads", ctrl.GetMessageReadDetail)
 	}
 }
--- a/backend/go-service/app/im/service/im_service.go
+++ b/backend/go-service/app/im/service/im_service.go
@@ -23,25 +23,30 @@ const (
 )

 var (
-	ErrNotFriend       = errors.New("对方不是你的好友")
-	ErrEmptyContent    = errors.New("消息内容不能为空")
-	ErrConvNotFound    = errors.New("会话不存在")
-	ErrMsgNotFound     = errors.New("消息不存在")
-	ErrNotSender       = errors.New("只能撤回自己发送的消息")
-	ErrRecallTimeout   = errors.New("超过撤回时限")
-	ErrNotMember       = errors.New("你不是该会话的成员")
-	ErrDuplicateMsg    = errors.New("重复消息")
-	ErrInvalidMsgType  = errors.New("不支持的消息类型")
+	ErrNotFriend        = errors.New("对方不是你的好友")
+	ErrEmptyContent     = errors.New("消息内容不能为空")
+	ErrConvNotFound     = errors.New("会话不存在")
+	ErrMsgNotFound      = errors.New("消息不存在")
+	ErrNotSender        = errors.New("只能撤回自己发送的消息")
+	ErrRecallTimeout    = errors.New("超过撤回时限")
+	ErrNotMember        = errors.New("你不是该会话的成员")
+	ErrDuplicateMsg     = errors.New("重复消息")
+	ErrInvalidMsgType   = errors.New("不支持的消息类型")
+	ErrGroupDissolved   = errors.New("群聊已解散")
+	ErrGroupAllMuted    = errors.New("当前群已开启全体禁言")
+	ErrUserMuted        = errors.New("你已被禁言，无法发送消息")
 )

 // IMService 即时通讯核心业务服务
 type IMService struct {
-	convDAO       *dao.ConversationDAO
-	msgDAO        *dao.MessageDAO
-	pubsub        *ws.PubSub
-	rdb           *redis.Client
-	friendChecker FriendChecker
+	convDAO        *dao.ConversationDAO
+	msgDAO         *dao.MessageDAO
+	pubsub         *ws.PubSub
+	rdb            *redis.Client
+	friendChecker  FriendChecker
 	userInfoGetter UserInfoGetter
+	groupInfo      GroupInfoGetter
+	readRecorder   MessageReadRecorder
 }

 // NewIMService 创建 IMService 实例
@@ -52,6 +57,8 @@ func NewIMService(
 	rdb *redis.Client,
 	friendChecker FriendChecker,
 	userInfoGetter UserInfoGetter,
+	groupInfo GroupInfoGetter,
+	readRecorder MessageReadRecorder,
 ) *IMService {
 	return &IMService{
 		convDAO:        convDAO,
@@ -60,15 +67,14 @@ func NewIMService(
 		rdb:            rdb,
 		friendChecker:  friendChecker,
 		userInfoGetter: userInfoGetter,
+		groupInfo:      groupInfo,
+		readRecorder:   readRecorder,
 	}
 }

-// SendMessage 发送消息（核心流程）
-// 1. 校验好友关系
-// 2. 查找或创建会话
-// 3. 幂等去重（client_msg_id）
-// 4. 写入消息 + 更新会话最后消息 + 递增对方未读数
-// 5. 通过 PubSub 推送给接收方
+// SendMessage 发送消息（核心流程，同时支持单聊和群聊）
+// 单聊：校验好友关系 → 查找/创建会话 → 写入消息 → 推送给对方
+// 群聊：校验群成员+禁言 → 写入消息（含 @信息）→ 推送给所有群成员
 func (s *IMService) SendMessage(ctx context.Context, senderID int64, req *dto.SendMessageRequest) (*dto.MessageDTO, error) {
 	funcName := "service.im_service.SendMessage"
 	logs.Info(ctx, funcName, "发送消息",
@@ -87,40 +93,64 @@ func (s *IMService) SendMessage(ctx context.Context, senderID int64, req *dto.Se
 	}

 	convID := req.ConversationID
-	var peerID int64

 	if convID == 0 && req.TargetUserID > 0 {
-		isFriend, err := s.friendChecker.IsFriend(ctx, senderID, req.TargetUserID)
-		if err != nil {
-			logs.Error(ctx, funcName, "检查好友关系失败", zap.Error(err))
-			return nil, err
-		}
-		if !isFriend {
-			return nil, ErrNotFriend
-		}
-
-		conv, err := s.getOrCreatePrivateConversation(ctx, senderID, req.TargetUserID)
-		if err != nil {
-			return nil, err
-		}
-		convID = conv.ID
-		peerID = req.TargetUserID
+		return s.sendPrivateMessage(ctx, senderID, req)
 	} else if convID > 0 {
-		member, err := s.convDAO.GetMember(ctx, convID, senderID)
+		conv, err := s.convDAO.GetByID(ctx, convID)
 		if err != nil {
-			return nil, ErrNotMember
+			return nil, ErrConvNotFound
 		}
-		if member == nil {
-			return nil, ErrNotMember
+		if conv.Type == constants.ConversationTypeGroup {
+			return s.sendGroupMessage(ctx, senderID, req)
 		}
-		peerID, err = s.convDAO.GetPeerUserID(ctx, convID, senderID)
-		if err != nil {
-			logs.Error(ctx, funcName, "查询对方用户 ID 失败", zap.Error(err))
-			return nil, err
-		}
-	} else {
-		return nil, ErrConvNotFound
+		return s.sendPrivateMessageByConvID(ctx, senderID, convID, req)
 	}
+	return nil, ErrConvNotFound
+}
+
+// sendPrivateMessage 发送单聊消息（首次发送，通过 TargetUserID）
+func (s *IMService) sendPrivateMessage(ctx context.Context, senderID int64, req *dto.SendMessageRequest) (*dto.MessageDTO, error) {
+	funcName := "service.im_service.sendPrivateMessage"
+
+	isFriend, err := s.friendChecker.IsFriend(ctx, senderID, req.TargetUserID)
+	if err != nil {
+		logs.Error(ctx, funcName, "检查好友关系失败", zap.Error(err))
+		return nil, err
+	}
+	if !isFriend {
+		return nil, ErrNotFriend
+	}
+
+	conv, err := s.getOrCreatePrivateConversation(ctx, senderID, req.TargetUserID)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.writeAndPushPrivateMessage(ctx, senderID, conv.ID, req.TargetUserID, req)
+}
+
+// sendPrivateMessageByConvID 发送单聊消息（已有会话 ID）
+func (s *IMService) sendPrivateMessageByConvID(ctx context.Context, senderID, convID int64, req *dto.SendMessageRequest) (*dto.MessageDTO, error) {
+	funcName := "service.im_service.sendPrivateMessageByConvID"
+
+	member, err := s.convDAO.GetMember(ctx, convID, senderID)
+	if err != nil || member == nil {
+		return nil, ErrNotMember
+	}
+
+	peerID, err := s.convDAO.GetPeerUserID(ctx, convID, senderID)
+	if err != nil {
+		logs.Error(ctx, funcName, "查询对方用户 ID 失败", zap.Error(err))
+		return nil, err
+	}
+
+	return s.writeAndPushPrivateMessage(ctx, senderID, convID, peerID, req)
+}
+
+// writeAndPushPrivateMessage 单聊：幂等去重 + 写消息 + 推送
+func (s *IMService) writeAndPushPrivateMessage(ctx context.Context, senderID, convID, peerID int64, req *dto.SendMessageRequest) (*dto.MessageDTO, error) {
+	funcName := "service.im_service.writeAndPushPrivateMessage"

 	if req.ClientMsgID != "" {
 		existing, err := s.msgDAO.FindByClientMsgID(ctx, convID, req.ClientMsgID)
@@ -160,40 +190,161 @@ func (s *IMService) SendMessage(ctx context.Context, senderID int64, req *dto.Se

 	s.incrementTotalUnread(ctx, peerID)

-	pushData := map[string]interface{}{
-		"id":              msg.ID,
-		"conversation_id": convID,
-		"sender_id":       senderID,
-		"type":            msg.Type,
-		"content":         msg.Content,
-		"client_msg_id":   msg.ClientMsgID,
-		"created_at":      msg.CreatedAt.Format("2006-01-02 15:04:05"),
-	}
-	if senderUsers, sErr := s.userInfoGetter.GetUsersByIDs(ctx, []int64{senderID}); sErr == nil && len(senderUsers) > 0 {
-		pushData["sender_name"] = senderUsers[0].Nickname
-		pushData["sender_avatar"] = senderUsers[0].Avatar
-	}
+	pushData := s.buildMessagePushData(ctx, msg, senderID)
+	pushData["conv_type"] = constants.ConversationTypePrivate
 	s.pushToUser(ctx, peerID, "im.message.new", pushData)

 	return s.toMessageDTO(msg), nil
 }

-// RecallMessage 撤回消息（2分钟内）
-// 撤回成功后，若被撤回消息是会话最后一条，则同步更新会话预览文本
-func (s *IMService) RecallMessage(ctx context.Context, senderID int64, messageID int64) error {
+// sendGroupMessage 发送群聊消息
+func (s *IMService) sendGroupMessage(ctx context.Context, senderID int64, req *dto.SendMessageRequest) (*dto.MessageDTO, error) {
+	funcName := "service.im_service.sendGroupMessage"
+	convID := req.ConversationID
+
+	member, err := s.convDAO.GetMember(ctx, convID, senderID)
+	if err != nil || member == nil {
+		return nil, ErrNotMember
+	}
+
+	if s.groupInfo != nil {
+		groupBrief, gErr := s.groupInfo.GetGroupBrief(ctx, convID)
+		if gErr != nil {
+			logs.Error(ctx, funcName, "获取群信息失败", zap.Error(gErr))
+			return nil, ErrConvNotFound
+		}
+		if groupBrief.Status == constants.GroupStatusDissolved {
+			return nil, ErrGroupDissolved
+		}
+		if groupBrief.IsAllMuted && member.Role < constants.GroupRoleAdmin {
+			return nil, ErrGroupAllMuted
+		}
+	}
+
+	if member.IsMuted {
+		return nil, ErrUserMuted
+	}
+
+	if req.ClientMsgID != "" {
+		existing, err := s.msgDAO.FindByClientMsgID(ctx, convID, req.ClientMsgID)
+		if err != nil {
+			logs.Error(ctx, funcName, "幂等去重查询失败", zap.Error(err))
+			return nil, err
+		}
+		if existing != nil {
+			return s.toMessageDTO(existing), ErrDuplicateMsg
+		}
+	}
+
+	msg := &model.Message{
+		ConversationID: convID,
+		SenderID:       senderID,
+		Type:           req.Type,
+		Content:        req.Content,
+		Status:         constants.MessageStatusNormal,
+		ClientMsgID:    req.ClientMsgID,
+	}
+	if len(req.AtUserIDs) > 0 {
+		msg.AtUserIDs = req.AtUserIDs
+	}
+	if err := s.msgDAO.Create(ctx, msg); err != nil {
+		return nil, err
+	}
+
+	now := time.Now()
+	if err := s.convDAO.UpdateLastMessage(ctx, convID, msg.ID, truncateContent(req.Content, 100), senderID, now); err != nil {
+		logs.Error(ctx, funcName, "更新最后消息失败", zap.Error(err))
+	}
+
+	memberIDs, err := s.convDAO.GetConversationMemberIDs(ctx, convID)
+	if err != nil {
+		logs.Error(ctx, funcName, "获取群成员列表失败", zap.Error(err))
+		return s.toMessageDTO(msg), nil
+	}
+
+	dndMap, dndErr := s.convDAO.GetMemberDNDMap(ctx, convID)
+	if dndErr != nil {
+		logs.Error(ctx, funcName, "获取免打扰状态失败", zap.Error(dndErr))
+		dndMap = make(map[int64]bool)
+	}
+
+	pushData := s.buildMessagePushData(ctx, msg, senderID)
+	pushData["conv_type"] = constants.ConversationTypeGroup
+	if len(req.AtUserIDs) > 0 {
+		pushData["at_user_ids"] = req.AtUserIDs
+	}
+
+	for _, uid := range memberIDs {
+		if uid == senderID {
+			continue
+		}
+		if err := s.convDAO.IncrementUnread(ctx, convID, uid); err != nil {
+			logs.Error(ctx, funcName, "递增未读计数失败", zap.Int64("user_id", uid), zap.Error(err))
+		}
+
+		if !dndMap[uid] {
+			s.incrementTotalUnread(ctx, uid)
+		}
+
+		if len(req.AtUserIDs) > 0 {
+			isAtMe := false
+			for _, atID := range req.AtUserIDs {
+				if atID == uid || atID == 0 {
+					isAtMe = true
+					break
+				}
+			}
+			if isAtMe {
+				if err := s.convDAO.IncrementAtMeCount(ctx, convID, uid); err != nil {
+					logs.Error(ctx, funcName, "递增@计数失败", zap.Int64("user_id", uid), zap.Error(err))
+				}
+			}
+		}
+
+		s.pushToUser(ctx, uid, "im.message.new", pushData)
+	}
+
+	return s.toMessageDTO(msg), nil
+}
+
+// RecallMessage 撤回消息
+// 单聊：只能撤回自己的消息，2 分钟内
+// 群聊：自己的消息 2 分钟内撤回；群主/管理员可无时限撤回任何消息
+func (s *IMService) RecallMessage(ctx context.Context, operatorID int64, messageID int64) error {
 	funcName := "service.im_service.RecallMessage"
 	logs.Info(ctx, funcName, "撤回消息",
-		zap.Int64("sender_id", senderID), zap.Int64("message_id", messageID))
+		zap.Int64("operator_id", operatorID), zap.Int64("message_id", messageID))

 	msg, err := s.msgDAO.GetByID(ctx, messageID)
 	if err != nil {
 		return ErrMsgNotFound
 	}
-	if msg.SenderID != senderID {
-		return ErrNotSender
+
+	conv, err := s.convDAO.GetByID(ctx, msg.ConversationID)
+	if err != nil {
+		logs.Error(ctx, funcName, "获取会话信息失败", zap.Error(err))
+		return ErrConvNotFound
 	}
-	if time.Since(msg.CreatedAt).Seconds() > float64(constants.MessageRecallTimeLimit) {
-		return ErrRecallTimeout
+
+	isAdmin := false
+	if conv.Type == constants.ConversationTypeGroup {
+		member, mErr := s.convDAO.GetMember(ctx, msg.ConversationID, operatorID)
+		if mErr != nil || member == nil {
+			return ErrNotMember
+		}
+		isAdmin = member.Role >= constants.GroupRoleAdmin
+	}
+
+	if msg.SenderID == operatorID {
+		if time.Since(msg.CreatedAt).Seconds() > float64(constants.MessageRecallTimeLimit) {
+			if !isAdmin {
+				return ErrRecallTimeout
+			}
+		}
+	} else {
+		if !isAdmin {
+			return ErrNotSender
+		}
 	}

 	if err := s.msgDAO.UpdateStatus(ctx, messageID, constants.MessageStatusRecalled); err != nil {
@@ -201,16 +352,31 @@ func (s *IMService) RecallMessage(ctx context.Context, senderID int64, messageID
 		return err
 	}

-	conv, err := s.convDAO.GetByID(ctx, msg.ConversationID)
-	if err != nil {
-		logs.Error(ctx, funcName, "获取会话信息失败", zap.Error(err))
-	} else if conv.LastMessageID != nil && *conv.LastMessageID == msg.ID {
-		senderInfo, infoErr := s.userInfoGetter.GetUsersByIDs(ctx, []int64{senderID})
-		recallText := "撤回了一条消息"
+	recallText := "撤回了一条消息"
+	if msg.SenderID != operatorID && isAdmin {
+		operatorInfo, infoErr := s.userInfoGetter.GetUsersByIDs(ctx, []int64{operatorID, msg.SenderID})
+		operatorName := "管理员"
+		senderName := "成员"
+		if infoErr == nil {
+			for _, u := range operatorInfo {
+				if u.ID == operatorID {
+					operatorName = u.Nickname
+				}
+				if u.ID == msg.SenderID {
+					senderName = u.Nickname
+				}
+			}
+		}
+		recallText = fmt.Sprintf("管理员 %s 撤回了 %s 的一条消息", operatorName, senderName)
+	} else {
+		senderInfo, infoErr := s.userInfoGetter.GetUsersByIDs(ctx, []int64{operatorID})
 		if infoErr == nil && len(senderInfo) > 0 {
 			recallText = senderInfo[0].Nickname + " 撤回了一条消息"
 		}
-		if updateErr := s.convDAO.UpdateLastMessage(ctx, msg.ConversationID, msg.ID, recallText, senderID, msg.CreatedAt); updateErr != nil {
+	}
+
+	if conv.LastMessageID != nil && *conv.LastMessageID == msg.ID {
+		if updateErr := s.convDAO.UpdateLastMessage(ctx, msg.ConversationID, msg.ID, recallText, operatorID, msg.CreatedAt); updateErr != nil {
 			logs.Error(ctx, funcName, "更新会话预览失败", zap.Error(updateErr))
 		}
 	}
@@ -221,20 +387,22 @@ func (s *IMService) RecallMessage(ctx context.Context, senderID int64, messageID
 		return nil
 	}
 	for _, uid := range memberIDs {
-		if uid == senderID {
+		if uid == operatorID {
 			continue
 		}
 		s.pushToUser(ctx, uid, "im.message.recalled", map[string]interface{}{
 			"message_id":      messageID,
 			"conversation_id": msg.ConversationID,
-			"sender_id":       senderID,
+			"operator_id":     operatorID,
+			"sender_id":       msg.SenderID,
+			"recall_text":     recallText,
 		})
 	}

 	return nil
 }

-// GetConversationList 获取会话列表（含对方用户信息）
+// GetConversationList 获取会话列表（含对方用户信息 / 群聊信息）
 func (s *IMService) GetConversationList(ctx context.Context, userID int64) (*dto.ConversationListResponse, error) {
 	funcName := "service.im_service.GetConversationList"
 	logs.Debug(ctx, funcName, "获取会话列表", zap.Int64("user_id", userID))
@@ -245,17 +413,20 @@ func (s *IMService) GetConversationList(ctx context.Context, userID int64) (*dto
 	}

 	peerIDs := make([]int64, 0, len(convs))
+	groupConvIDs := make([]int64, 0)
 	for _, c := range convs {
-		if c.PeerUserID > 0 {
+		if c.Type == constants.ConversationTypePrivate && c.PeerUserID > 0 {
 			peerIDs = append(peerIDs, c.PeerUserID)
+		} else if c.Type == constants.ConversationTypeGroup {
+			groupConvIDs = append(groupConvIDs, c.ID)
 		}
 	}

 	userMap := make(map[int64]*userBrief)
 	if len(peerIDs) > 0 {
-		users, err := s.userInfoGetter.GetUsersByIDs(ctx, peerIDs)
-		if err != nil {
-			logs.Error(ctx, funcName, "批量查询用户信息失败", zap.Error(err))
+		users, uErr := s.userInfoGetter.GetUsersByIDs(ctx, peerIDs)
+		if uErr != nil {
+			logs.Error(ctx, funcName, "批量查询用户信息失败", zap.Error(uErr))
 		} else {
 			for i := range users {
 				u := users[i]
@@ -264,17 +435,31 @@ func (s *IMService) GetConversationList(ctx context.Context, userID int64) (*dto
 		}
 	}

+	groupMap := make(map[int64]*dto.GroupBrief)
+	if s.groupInfo != nil && len(groupConvIDs) > 0 {
+		for _, convID := range groupConvIDs {
+			brief, gErr := s.groupInfo.GetGroupBrief(ctx, convID)
+			if gErr != nil {
+				logs.Error(ctx, funcName, "获取群信息失败",
+					zap.Int64("conversation_id", convID), zap.Error(gErr))
+				continue
+			}
+			groupMap[convID] = brief
+		}
+	}
+
 	list := make([]dto.ConversationDTO, 0, len(convs))
 	for _, c := range convs {
-		peerID := c.PeerUserID
 		item := dto.ConversationDTO{
 			ID:              c.ID,
 			Type:            c.Type,
-			PeerUserID:      peerID,
+			PeerUserID:      c.PeerUserID,
 			LastMsgContent:  c.LastMsgContent,
 			LastMsgSenderID: c.LastMsgSenderID,
 			IsPinned:        c.IsPinned,
 			UnreadCount:     c.UnreadCount,
+			IsDoNotDisturb:  c.IsDoNotDisturb,
+			AtMeCount:       c.AtMeCount,
 		}
 		if c.ClearBeforeMsgID > 0 && c.LastMessageID != nil && *c.LastMessageID <= c.ClearBeforeMsgID {
 			item.LastMsgContent = ""
@@ -283,10 +468,20 @@ func (s *IMService) GetConversationList(ctx context.Context, userID int64) (*dto
 		if c.LastMsgTime != nil {
 			item.LastMsgTime = c.LastMsgTime.Format("2006-01-02 15:04:05")
 		}
-		if brief, ok := userMap[peerID]; ok {
-			item.PeerNickname = brief.Nickname
-			item.PeerAvatar = brief.Avatar
+
+		if c.Type == constants.ConversationTypePrivate {
+			if brief, ok := userMap[c.PeerUserID]; ok {
+				item.PeerNickname = brief.Nickname
+				item.PeerAvatar = brief.Avatar
+			}
+		} else if c.Type == constants.ConversationTypeGroup {
+			if gBrief, ok := groupMap[c.ID]; ok {
+				item.PeerNickname = gBrief.Name
+				item.PeerAvatar = gBrief.Avatar
+				item.GroupID = gBrief.ID
+			}
 		}
+
 		list = append(list, item)
 	}

@@ -360,6 +555,133 @@ func (s *IMService) MarkRead(ctx context.Context, userID int64, conversationID i
 	return nil
 }

+// MarkGroupMessagesRead 标记群聊消息已读（消息级别）
+// 将指定消息标记为已读 + 推送已读计数变化给消息发送者
+func (s *IMService) MarkGroupMessagesRead(ctx context.Context, userID int64, req *dto.MarkGroupReadRequest) error {
+	funcName := "service.im_service.MarkGroupMessagesRead"
+	logs.Info(ctx, funcName, "群消息标记已读",
+		zap.Int64("user_id", userID), zap.Int64("conversation_id", req.ConversationID),
+		zap.Int("msg_count", len(req.MessageIDs)))
+
+	member, err := s.convDAO.GetMember(ctx, req.ConversationID, userID)
+	if err != nil || member == nil {
+		return ErrNotMember
+	}
+
+	if s.readRecorder == nil || len(req.MessageIDs) == 0 {
+		return nil
+	}
+
+	if err := s.readRecorder.BatchCreateReads(ctx, req.MessageIDs, userID); err != nil {
+		logs.Error(ctx, funcName, "批量创建已读记录失败", zap.Error(err))
+		return err
+	}
+
+	if member.AtMeCount > 0 {
+		if err := s.convDAO.ClearAtMeCount(ctx, req.ConversationID, userID); err != nil {
+			logs.Error(ctx, funcName, "清零@计数失败", zap.Error(err))
+		}
+	}
+
+	readCounts, err := s.readRecorder.GetReadCountBatch(ctx, req.MessageIDs)
+	if err != nil {
+		logs.Error(ctx, funcName, "获取已读计数失败", zap.Error(err))
+		return nil
+	}
+
+	for _, msgID := range req.MessageIDs {
+		msg, mErr := s.msgDAO.GetByID(ctx, msgID)
+		if mErr != nil || msg.SenderID == userID {
+			continue
+		}
+		count := readCounts[msgID]
+		s.pushToUser(ctx, msg.SenderID, "im.message.read.count", map[string]interface{}{
+			"message_id":      msgID,
+			"conversation_id": req.ConversationID,
+			"read_count":      count,
+		})
+	}
+
+	return nil
+}
+
+// GetMessageReadDetail 获取消息已读详情（已读/未读用户列表）
+func (s *IMService) GetMessageReadDetail(ctx context.Context, userID int64, messageID int64) (*dto.GetReadDetailResponse, error) {
+	funcName := "service.im_service.GetMessageReadDetail"
+	logs.Debug(ctx, funcName, "获取已读详情",
+		zap.Int64("user_id", userID), zap.Int64("message_id", messageID))
+
+	msg, err := s.msgDAO.GetByID(ctx, messageID)
+	if err != nil {
+		return nil, ErrMsgNotFound
+	}
+
+	member, err := s.convDAO.GetMember(ctx, msg.ConversationID, userID)
+	if err != nil || member == nil {
+		return nil, ErrNotMember
+	}
+
+	memberIDs, err := s.convDAO.GetConversationMemberIDs(ctx, msg.ConversationID)
+	if err != nil {
+		return nil, err
+	}
+
+	readUserIDs := make(map[int64]bool)
+	if s.readRecorder != nil {
+		ids, rErr := s.readRecorder.GetReadUserIDs(ctx, messageID)
+		if rErr != nil {
+			logs.Error(ctx, funcName, "获取已读用户列表失败", zap.Error(rErr))
+		} else {
+			for _, id := range ids {
+				readUserIDs[id] = true
+			}
+		}
+	}
+
+	allUserIDs := make([]int64, 0, len(memberIDs))
+	for _, id := range memberIDs {
+		if id != msg.SenderID {
+			allUserIDs = append(allUserIDs, id)
+		}
+	}
+
+	userMap := make(map[int64]*userBrief)
+	if len(allUserIDs) > 0 {
+		users, uErr := s.userInfoGetter.GetUsersByIDs(ctx, allUserIDs)
+		if uErr != nil {
+			logs.Error(ctx, funcName, "批量查询用户信息失败", zap.Error(uErr))
+		} else {
+			for i := range users {
+				u := users[i]
+				userMap[u.ID] = &userBrief{Nickname: u.Nickname, Avatar: u.Avatar}
+			}
+		}
+	}
+
+	var readList, unreadList []dto.MessageReadDetailDTO
+	for _, uid := range allUserIDs {
+		item := dto.MessageReadDetailDTO{
+			UserID: uid,
+		}
+		if brief, ok := userMap[uid]; ok {
+			item.UserNickname = brief.Nickname
+			item.UserAvatar = brief.Avatar
+		}
+		if readUserIDs[uid] {
+			readList = append(readList, item)
+		} else {
+			unreadList = append(unreadList, item)
+		}
+	}
+
+	return &dto.GetReadDetailResponse{
+		ReadList:   readList,
+		UnreadList: unreadList,
+		ReadCount:  len(readList),
+		TotalCount: len(allUserIDs),
+	}, nil
+}
+
 // PinConversation 置顶/取消置顶会话
 func (s *IMService) PinConversation(ctx context.Context, userID int64, conversationID int64, isPinned bool) error {
 	funcName := "service.im_service.PinConversation"
@@ -580,7 +902,7 @@ func (s *IMService) decrementTotalUnread(ctx context.Context, userID int64, coun

 // toMessageDTO 将 model.Message 转换为 dto.MessageDTO
 func (s *IMService) toMessageDTO(m *model.Message) *dto.MessageDTO {
-	return &dto.MessageDTO{
+	d := &dto.MessageDTO{
 		ID:             m.ID,
 		ConversationID: m.ConversationID,
 		SenderID:       m.SenderID,
@@ -590,6 +912,28 @@ func (s *IMService) toMessageDTO(m *model.Message) *dto.MessageDTO {
 		ClientMsgID:    m.ClientMsgID,
 		CreatedAt:      m.CreatedAt.Format("2006-01-02 15:04:05"),
 	}
+	if len(m.AtUserIDs) > 0 {
+		d.AtUserIDs = []int64(m.AtUserIDs)
+	}
+	return d
+}
+
+// buildMessagePushData 构建消息推送数据（单聊/群聊通用）
+func (s *IMService) buildMessagePushData(ctx context.Context, msg *model.Message, senderID int64) map[string]interface{} {
+	pushData := map[string]interface{}{
+		"id":              msg.ID,
+		"conversation_id": msg.ConversationID,
+		"sender_id":       senderID,
+		"type":            msg.Type,
+		"content":         msg.Content,
+		"client_msg_id":   msg.ClientMsgID,
+		"created_at":      msg.CreatedAt.Format("2006-01-02 15:04:05"),
+	}
+	if senderUsers, sErr := s.userInfoGetter.GetUsersByIDs(ctx, []int64{senderID}); sErr == nil && len(senderUsers) > 0 {
+		pushData["sender_name"] = senderUsers[0].Nickname
+		pushData["sender_avatar"] = senderUsers[0].Avatar
+	}
+	return pushData
 }

 // userBrief 用户简要信息（内部使用）
--- a/backend/go-service/app/im/service/interfaces.go
+++ b/backend/go-service/app/im/service/interfaces.go
@@ -5,6 +5,7 @@ import (
 	"context"

 	authModel "github.com/echochat/backend/app/auth/model"
+	"github.com/echochat/backend/app/dto"
 )

 // FriendChecker 好友关系校验接口
@@ -18,3 +19,19 @@ type FriendChecker interface {
 type UserInfoGetter interface {
 	GetUsersByIDs(ctx context.Context, userIDs []int64) ([]authModel.User, error)
 }
+
+// GroupInfoGetter 群信息查询接口（Phase 2c）
+// 由 group.GroupDAO 隐式实现，通过 Wire 接口注入
+// IM 模块通过此接口获取群表信息（判断全体禁言、已解散等）
+// 成员信息（角色/禁言/列表）通过 convDAO 直接查询 im_conversation_members 表
+type GroupInfoGetter interface {
+	GetGroupBrief(ctx context.Context, conversationID int64) (*dto.GroupBrief, error)
+}
+
+// MessageReadRecorder 群消息已读记录接口（Phase 2c）
+// 由 group.MessageReadDAO 隐式实现
+type MessageReadRecorder interface {
+	BatchCreateReads(ctx context.Context, messageIDs []int64, userID int64) error
+	GetReadCountBatch(ctx context.Context, messageIDs []int64) (map[int64]int, error)
+	GetReadUserIDs(ctx context.Context, messageID int64) ([]int64, error)
+}
--- a/backend/go-service/app/provider/provider.go
+++ b/backend/go-service/app/provider/provider.go
@@ -7,13 +7,17 @@ import (
 	authController "github.com/echochat/backend/app/auth/controller"
 	"github.com/echochat/backend/app/auth/service"
 	contactController "github.com/echochat/backend/app/contact/controller"
+	fileController "github.com/echochat/backend/app/file/controller"
+	groupController "github.com/echochat/backend/app/group/controller"
 	imController "github.com/echochat/backend/app/im/controller"
 	imHandler "github.com/echochat/backend/app/im/handler"
 	wsApp "github.com/echochat/backend/app/ws"
 	"github.com/echochat/backend/config"
 	"github.com/echochat/backend/pkg/db"
+	"github.com/echochat/backend/pkg/storage"
 	"github.com/echochat/backend/pkg/ws"
 	"github.com/google/wire"
+	"github.com/minio/minio-go/v7"
 	"github.com/redis/go-redis/v9"
 	"gorm.io/gorm"
 )
@@ -23,12 +27,14 @@ type App struct {
 	Config                *config.Config
 	DB                    *gorm.DB
 	Redis                 *redis.Client
+	MinioClient           *minio.Client                               // MinIO 对象存储客户端
 	AuthService           *service.AuthService                        // Auth 认证服务
 	AuthController        *authController.AuthController              // 前台认证控制器
 	AdminAuthController   *authController.AdminAuthController         // 后台认证控制器
 	UserManageController    *adminController.UserManageController       // 管理端用户管理控制器
 	OnlineController        *adminController.OnlineController           // 管理端在线监控控制器
 	ContactManageController *adminController.ContactManageController    // 管理端好友关系管理控制器
+	GroupManageController   *adminController.GroupManageController      // 管理端群组管理控制器
 	WSHandler             *wsApp.Handler                              // WebSocket 连接处理器
 	Hub                   *ws.Hub                                     // WebSocket Hub 连接管理
 	PubSub                *ws.PubSub                                  // Redis Pub/Sub 消息路由
@@ -37,6 +43,8 @@ type App struct {
 	IMController          *imController.IMController                 // IM 即时通讯控制器
 	IMEventHandler        *imHandler.EventHandler                    // IM WS 事件处理器
 	OfflinePusher         *imHandler.OfflinePusher                   // 离线消息推送器
+	FileController        *fileController.FileController             // 文件上传控制器
+	GroupController       *groupController.GroupController           // 群聊管理控制器
 }

 // NewApp 创建应用实例
@@ -44,12 +52,14 @@ func NewApp(
 	cfg *config.Config,
 	gormDB *gorm.DB,
 	redisClient *redis.Client,
+	minioClient *minio.Client,
 	authService *service.AuthService,
 	authCtrl *authController.AuthController,
 	adminAuthCtrl *authController.AdminAuthController,
 	userManageCtrl *adminController.UserManageController,
 	onlineCtrl *adminController.OnlineController,
 	contactManageCtrl *adminController.ContactManageController,
+	groupManageCtrl *adminController.GroupManageController,
 	wsHandler *wsApp.Handler,
 	hub *ws.Hub,
 	pubsub *ws.PubSub,
@@ -58,6 +68,8 @@ func NewApp(
 	imCtrl *imController.IMController,
 	imEventHandler *imHandler.EventHandler,
 	offlinePusher *imHandler.OfflinePusher,
+	fileCtrl *fileController.FileController,
+	groupCtrl *groupController.GroupController,
 ) *App {
 	// 注入离线消息推送器到 WS Handler
 	wsHandler.SetOfflinePusher(offlinePusher)
@@ -66,12 +78,14 @@ func NewApp(
 		Config:                  cfg,
 		DB:                      gormDB,
 		Redis:                   redisClient,
+		MinioClient:             minioClient,
 		AuthService:             authService,
 		AuthController:          authCtrl,
 		AdminAuthController:     adminAuthCtrl,
 		UserManageController:    userManageCtrl,
 		OnlineController:        onlineCtrl,
 		ContactManageController: contactManageCtrl,
+		GroupManageController:   groupManageCtrl,
 		WSHandler:               wsHandler,
 		Hub:                     hub,
 		PubSub:                  pubsub,
@@ -80,6 +94,8 @@ func NewApp(
 		IMController:            imCtrl,
 		IMEventHandler:          imEventHandler,
 		OfflinePusher:           offlinePusher,
+		FileController:          fileCtrl,
+		GroupController:         groupCtrl,
 	}
 }

@@ -98,12 +114,19 @@ func provideJWTConfig(cfg *config.Config) *config.JWTConfig {
 	return &cfg.JWT
 }

+// provideMinioConfig 从全局 Config 中提取 MinioConfig
+func provideMinioConfig(cfg *config.Config) *config.MinioConfig {
+	return &cfg.Minio
+}
+
 // InfraSet 基础设施层 Provider Set
 var InfraSet = wire.NewSet(
 	provideDBConfig,
 	provideRedisConfig,
 	provideJWTConfig,
+	provideMinioConfig,
 	db.NewPostgres,
 	db.NewRedis,
+	storage.NewMinioClient,
 	NewApp,
 )
--- a/backend/go-service/app/provider/wire.go
+++ b/backend/go-service/app/provider/wire.go
@@ -6,11 +6,16 @@ package provider
 import (
 	"github.com/echochat/backend/app/admin"
 	"github.com/echochat/backend/app/auth"
-	"github.com/echochat/backend/app/contact"
 	authService "github.com/echochat/backend/app/auth/service"
+	"github.com/echochat/backend/app/contact"
 	contactDAO "github.com/echochat/backend/app/contact/dao"
 	contactService "github.com/echochat/backend/app/contact/service"
+	fileApp "github.com/echochat/backend/app/file"
+	groupApp "github.com/echochat/backend/app/group"
+	groupDAO "github.com/echochat/backend/app/group/dao"
+	groupService "github.com/echochat/backend/app/group/service"
 	imApp "github.com/echochat/backend/app/im"
+	imDAO "github.com/echochat/backend/app/im/dao"
 	imService "github.com/echochat/backend/app/im/service"
 	wsApp "github.com/echochat/backend/app/ws"
 	"github.com/echochat/backend/config"
@@ -26,11 +31,17 @@ func InitializeApp(cfg *config.Config) (*App, error) {
 		wsApp.WSSet,
 		contact.ContactSet,
 		imApp.IMSet,
+		fileApp.FileSet,
+		groupApp.GroupSet,
 		wire.Bind(new(wsApp.FriendIDsGetter), new(*contactDAO.FriendshipDAO)),
+		wire.Bind(new(groupService.UserInfoProvider), new(*contactDAO.FriendshipDAO)),
+		wire.Bind(new(imService.GroupInfoGetter), new(*groupDAO.GroupDAO)),
+		wire.Bind(new(imService.MessageReadRecorder), new(*groupDAO.MessageReadDAO)),
 		wire.Bind(new(wsApp.TokenValidator), new(*authService.AuthService)),
 		wire.Bind(new(imService.FriendChecker), new(*contactDAO.FriendshipDAO)),
 		wire.Bind(new(imService.UserInfoGetter), new(*contactDAO.FriendshipDAO)),
 		wire.Bind(new(contactService.OnlineChecker), new(*wsApp.OnlineService)),
+		wire.Bind(new(groupService.MessageWriter), new(*imDAO.MessageDAO)),
 	)
 	return nil, nil
 }
--- a/backend/go-service/app/provider/wire_gen.go
+++ b/backend/go-service/app/provider/wire_gen.go
@@ -16,10 +16,16 @@ import (
 	controller3 "github.com/echochat/backend/app/contact/controller"
 	dao3 "github.com/echochat/backend/app/contact/dao"
 	service3 "github.com/echochat/backend/app/contact/service"
+	controller4 "github.com/echochat/backend/app/file/controller"
+	service4 "github.com/echochat/backend/app/file/service"
+	controller5 "github.com/echochat/backend/app/group/controller"
+	dao4 "github.com/echochat/backend/app/group/dao"
+	service5 "github.com/echochat/backend/app/group/service"
 	imApp "github.com/echochat/backend/app/im"
 	"github.com/echochat/backend/app/ws"
 	"github.com/echochat/backend/config"
 	"github.com/echochat/backend/pkg/db"
+	"github.com/echochat/backend/pkg/storage"
 )

 // Injectors from wire.go:
@@ -36,6 +42,11 @@ func InitializeApp(cfg *config.Config) (*App, error) {
 	if err != nil {
 		return nil, err
 	}
+	minioConfig := provideMinioConfig(cfg)
+	minioClient, err := storage.NewMinioClient(minioConfig)
+	if err != nil {
+		return nil, err
+	}
 	userDAO := dao.NewUserDAO(gormDB)
 	roleDAO := dao.NewRoleDAO(gormDB)
 	jwtConfig := provideJWTConfig(cfg)
@@ -62,11 +73,26 @@ func InitializeApp(cfg *config.Config) (*App, error) {
 	// IM 模块初始化
 	conversationDAO := imApp.ProvideConversationDAO(gormDB)
 	messageDAO := imApp.ProvideMessageDAO(gormDB)
-	imService := imApp.ProvideIMService(conversationDAO, messageDAO, pubSub, client, friendshipDAO, friendshipDAO)
+	groupDAO := dao4.NewGroupDAO(gormDB)
+	messageReadDAO := dao4.NewMessageReadDAO(gormDB)
+	imService := imApp.ProvideIMService(conversationDAO, messageDAO, pubSub, client, friendshipDAO, friendshipDAO, groupDAO, messageReadDAO)
 	imEventHandler := imApp.ProvideIMEventHandler(imService, hub)
 	offlinePusher := imApp.ProvideOfflinePusher(imService, conversationDAO, pubSub)
 	imController := imApp.ProvideIMController(imService)

-	app := NewApp(cfg, gormDB, client, authService, authController, adminAuthController, userManageController, onlineController, contactManageController, handler, hub, pubSub, onlineService, contactController, imController, imEventHandler, offlinePusher)
+	// File 模块初始化
+	fileService := service4.NewFileService(minioClient, minioConfig)
+	fileController := controller4.NewFileController(fileService)
+
+	// Group 模块初始化
+	joinRequestDAO := dao4.NewJoinRequestDAO(gormDB)
+	groupService := service5.NewGroupService(groupDAO, joinRequestDAO, friendshipDAO, pubSub, messageDAO)
+	groupController := controller5.NewGroupController(groupService)
+
+	// Admin 群组管理初始化
+	groupManageService := service2.NewGroupManageService(gormDB, groupDAO)
+	groupManageController := controller2.NewGroupManageController(groupManageService)
+
+	app := NewApp(cfg, gormDB, client, minioClient, authService, authController, adminAuthController, userManageController, onlineController, contactManageController, groupManageController, handler, hub, pubSub, onlineService, contactController, imController, imEventHandler, offlinePusher, fileController, groupController)
 	return app, nil
 }
--- a/backend/go-service/config/config.dev.yaml
+++ b/backend/go-service/config/config.dev.yaml
@@ -45,3 +45,11 @@ log:
    max_backups: 10    # 保留的旧日志归档文件最大数量，超出的自动删除
    max_age: 30        # 旧日志归档文件保留天数，超过天数的自动删除
    compress: false    # 是否对归档的旧日志文件进行 gzip 压缩（生产环境建议 true）
+
+# MinIO 对象存储配置
+minio:
+  endpoint: "localhost:9000"           # MinIO 服务地址
+  access_key: "echochat"               # 访问密钥（与 docker-compose 中的 MINIO_ROOT_USER 一致）
+  secret_key: "echochat123456"         # 密钥（与 docker-compose 中的 MINIO_ROOT_PASSWORD 一致）
+  bucket: "echochat"                   # 存储桶名称
+  use_ssl: false                       # 开发环境不使用 HTTPS
--- a/backend/go-service/config/config.docker.yaml
+++ b/backend/go-service/config/config.docker.yaml
@@ -40,3 +40,10 @@ log:
    max_backups: 10
    max_age: 30
    compress: false
+
+minio:
+  endpoint: "minio:9000"
+  access_key: "echochat"
+  secret_key: "echochat123456"
+  bucket: "echochat"
+  use_ssl: false
--- a/backend/go-service/config/config.go
+++ b/backend/go-service/config/config.go
@@ -16,6 +16,16 @@ type Config struct {
 	Redis    RedisConfig    `mapstructure:"redis"`
 	JWT      JWTConfig      `mapstructure:"jwt"`
 	Log      LogConfig      `mapstructure:"log"`
+	Minio    MinioConfig    `mapstructure:"minio"`
+}
+
+// MinioConfig MinIO 对象存储配置
+type MinioConfig struct {
+	Endpoint  string `mapstructure:"endpoint"`   // MinIO 服务地址（host:port）
+	AccessKey string `mapstructure:"access_key"` // 访问密钥
+	SecretKey string `mapstructure:"secret_key"` // 密钥
+	Bucket    string `mapstructure:"bucket"`     // 存储桶名称
+	UseSSL    bool   `mapstructure:"use_ssl"`    // 是否使用 HTTPS
 }

 // ServerConfig HTTP 服务配置
--- a/backend/go-service/go.mod
+++ b/backend/go-service/go.mod
@@ -8,6 +8,7 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/google/wire v0.7.0
 	github.com/gorilla/websocket v1.5.3
+	github.com/minio/minio-go/v7 v7.0.83
 	github.com/redis/go-redis/v9 v9.18.0
 	github.com/spf13/viper v1.21.0
 	go.uber.org/zap v1.27.1
@@ -23,14 +24,16 @@ require (
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/cloudwego/base64x v0.1.6 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.8 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
+	github.com/go-ini/ini v1.67.0 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
 	github.com/go-playground/validator/v10 v10.27.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
-	github.com/goccy/go-json v0.10.2 // indirect
+	github.com/goccy/go-json v0.10.4 // indirect
 	github.com/goccy/go-yaml v1.18.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
@@ -39,14 +42,17 @@ require (
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/compress v1.17.11 // indirect
 	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/minio/md5-simd v1.1.2 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/quic-go/qpack v0.5.1 // indirect
 	github.com/quic-go/quic-go v0.54.0 // indirect
+	github.com/rs/xid v1.6.0 // indirect
 	github.com/sagikazarmark/locafero v0.11.0 // indirect
 	github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 // indirect
 	github.com/spf13/afero v1.15.0 // indirect
--- a/backend/go-service/go.sum
+++ b/backend/go-service/go.sum
@@ -15,6 +15,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
@@ -25,6 +27,8 @@ github.com/gin-contrib/sse v1.1.0 h1:n0w2GMuUpWDVp7qSpvze6fAu9iRxJY4Hmj6AmBOU05w
 github.com/gin-contrib/sse v1.1.0/go.mod h1:hxRZ5gVpWMT7Z0B0gSNYqqsSCNIJMjzvm6fqCz9vjwM=
 github.com/gin-gonic/gin v1.11.0 h1:OW/6PLjyusp2PPXtyxKHU0RbX6I/l28FTdDlae5ueWk=
 github.com/gin-gonic/gin v1.11.0/go.mod h1:+iq/FyxlGzII0KHiBGjuNn4UNENUlKbGlNmc+W50Dls=
+github.com/go-ini/ini v1.67.0 h1:z6ZrTEZqSWOTyH2FlglNbNgARyHG8oLW9gMELqKr06A=
+github.com/go-ini/ini v1.67.0/go.mod h1:ByCAeIL28uOIIG0E3PJtZPDL8WnHpFKFOtgjp+3Ies8=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
 github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
@@ -35,8 +39,8 @@ github.com/go-playground/validator/v10 v10.27.0 h1:w8+XrWVMhGkxOaaowyKH35gFydVHO
 github.com/go-playground/validator/v10 v10.27.0/go.mod h1:I5QpIEbmr8On7W0TktmJAumgzX4CA1XNl4ZmDuVHKKo=
 github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
 github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
-github.com/goccy/go-json v0.10.2 h1:CrxCmQqYDkv1z7lO7Wbh2HN93uovUHgrECaO5ZrCXAU=
-github.com/goccy/go-json v0.10.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
+github.com/goccy/go-json v0.10.4 h1:JSwxQzIqKfmFX1swYPpUThQZp/Ka4wzJdK0LWVytLPM=
+github.com/goccy/go-json v0.10.4/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
 github.com/goccy/go-yaml v1.18.0 h1:8W7wMFS12Pcas7KU+VVkaiCng+kG8QiFeFwzFb+rwuw=
 github.com/goccy/go-yaml v1.18.0/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
 github.com/golang-jwt/jwt/v5 v5.2.1 h1:OuVbFODueb089Lh128TAcimifWaLhJwVflnrgM17wHk=
@@ -64,6 +68,9 @@ github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
 github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
+github.com/klauspost/compress v1.17.11 h1:In6xLpyWOi1+C7tXUUWv2ot1QvBjxevKAaI6IXrJmUc=
+github.com/klauspost/compress v1.17.11/go.mod h1:pMDklpSncoRMuLFrf1W9Ss9KT+0rH90U12bZKk7uwG0=
+github.com/klauspost/cpuid/v2 v2.0.1/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
 github.com/klauspost/cpuid/v2 v2.3.0 h1:S4CRMLnYUhGeDFDqkGriYKdfoFlDnMtqTiI/sFzhA9Y=
 github.com/klauspost/cpuid/v2 v2.3.0/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
@@ -74,6 +81,10 @@ github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
 github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/minio/md5-simd v1.1.2 h1:Gdi1DZK69+ZVMoNHRXJyNcxrMA4dSxoYHZSQbirFg34=
+github.com/minio/md5-simd v1.1.2/go.mod h1:MzdKDxYpY2BT9XQFocsiZf/NKVtR7nkE4RoEpN+20RM=
+github.com/minio/minio-go/v7 v7.0.83 h1:W4Kokksvlz3OKf3OqIlzDNKd4MERlC2oN8YptwJ0+GA=
+github.com/minio/minio-go/v7 v7.0.83/go.mod h1:57YXpvc5l3rjPdhqNrDsvVlY0qPI6UTk1bflAe+9doY=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 h1:ZqeYNhU3OHLH3mGKHDcjJRFFRrJa6eAM5H+CtDdOsPc=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9Gz0M=
@@ -90,6 +101,8 @@ github.com/redis/go-redis/v9 v9.18.0 h1:pMkxYPkEbMPwRdenAzUNyFNrDgHx9U+DrBabWNfS
 github.com/redis/go-redis/v9 v9.18.0/go.mod h1:k3ufPphLU5YXwNTUcCRXGxUoF1fqxnhFQmscfkCoDA0=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
+github.com/rs/xid v1.6.0 h1:fV591PaemRlL6JfRxGDEPl69wICngIQ3shQtzfy2gxU=
+github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
 github.com/sagikazarmark/locafero v0.11.0 h1:1iurJgmM9G3PA/I+wWYIOw/5SyBtxapeHDcg+AAIFXc=
 github.com/sagikazarmark/locafero v0.11.0/go.mod h1:nVIGvgyzw595SUSUE6tvCp3YYTeHs15MvlmU87WwIik=
 github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 h1:+jumHNA0Wrelhe64i8F6HNlS8pkoyMv5sreGx2Ry5Rw=
--- a/backend/go-service/pkg/storage/minio.go
+++ b/backend/go-service/pkg/storage/minio.go
@@ -0,0 +1,38 @@
+// Package storage 提供对象存储基础设施
+// 封装 MinIO 客户端初始化和存储桶自动创建逻辑
+package storage
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/echochat/backend/config"
+	"github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+)
+
+// NewMinioClient 初始化 MinIO 客户端并确保存储桶存在
+// 启动时自动创建配置中指定的 bucket（如不存在）
+func NewMinioClient(cfg *config.MinioConfig) (*minio.Client, error) {
+	client, err := minio.New(cfg.Endpoint, &minio.Options{
+		Creds:  credentials.NewStaticV4(cfg.AccessKey, cfg.SecretKey, ""),
+		Secure: cfg.UseSSL,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("创建 MinIO 客户端失败: %w", err)
+	}
+
+	ctx := context.Background()
+	exists, err := client.BucketExists(ctx, cfg.Bucket)
+	if err != nil {
+		return nil, fmt.Errorf("检查存储桶 %s 失败: %w", cfg.Bucket, err)
+	}
+
+	if !exists {
+		if err := client.MakeBucket(ctx, cfg.Bucket, minio.MakeBucketOptions{}); err != nil {
+			return nil, fmt.Errorf("创建存储桶 %s 失败: %w", cfg.Bucket, err)
+		}
+	}
+
+	return client, nil
+}
--- a/backend/go-service/pkg/utils/int64_array.go
+++ b/backend/go-service/pkg/utils/int64_array.go
@@ -0,0 +1,70 @@
+// Package utils 提供通用工具类型和函数
+package utils
+
+import (
+	"database/sql/driver"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Int64Array 自定义 PostgreSQL BIGINT[] 类型
+// 实现 sql.Scanner 和 driver.Valuer 接口，用于 GORM 与 PostgreSQL 数组字段交互
+type Int64Array []int64
+
+// Scan 从数据库读取 PostgreSQL BIGINT[] 格式：{1,2,3}
+func (a *Int64Array) Scan(src interface{}) error {
+	if src == nil {
+		*a = nil
+		return nil
+	}
+
+	var s string
+	switch v := src.(type) {
+	case []byte:
+		s = string(v)
+	case string:
+		s = v
+	default:
+		return fmt.Errorf("Int64Array.Scan: 不支持的类型 %T", src)
+	}
+
+	s = strings.TrimSpace(s)
+	if s == "{}" || s == "" {
+		*a = Int64Array{}
+		return nil
+	}
+
+	s = strings.Trim(s, "{}")
+	parts := strings.Split(s, ",")
+	result := make(Int64Array, 0, len(parts))
+	for _, p := range parts {
+		p = strings.TrimSpace(p)
+		if p == "" {
+			continue
+		}
+		n, err := strconv.ParseInt(p, 10, 64)
+		if err != nil {
+			return fmt.Errorf("Int64Array.Scan: 解析 '%s' 失败: %w", p, err)
+		}
+		result = append(result, n)
+	}
+	*a = result
+	return nil
+}
+
+// Value 写入数据库时转换为 PostgreSQL BIGINT[] 格式：{1,2,3}
+func (a Int64Array) Value() (driver.Value, error) {
+	if a == nil {
+		return nil, nil
+	}
+	if len(a) == 0 {
+		return "{}", nil
+	}
+
+	parts := make([]string, len(a))
+	for i, v := range a {
+		parts[i] = strconv.FormatInt(v, 10)
+	}
+	return "{" + strings.Join(parts, ",") + "}", nil
+}
--- a/backend/go-service/router/router.go
+++ b/backend/go-service/router/router.go
@@ -9,6 +9,8 @@ import (
 	"github.com/echochat/backend/app/admin"
 	"github.com/echochat/backend/app/auth"
 	"github.com/echochat/backend/app/contact"
+	fileApp "github.com/echochat/backend/app/file"
+	groupApp "github.com/echochat/backend/app/group"
 	imApp "github.com/echochat/backend/app/im"
 	"github.com/echochat/backend/app/provider"
 	wsApp "github.com/echochat/backend/app/ws"
@@ -34,10 +36,12 @@ func Setup(engine *gin.Engine, app *provider.App) {

 	// --- 各模块路由注册 ---
 	auth.RegisterRoutes(engine, app.AuthController, app.AdminAuthController, jwtAuth)
-	admin.RegisterRoutes(engine, app.UserManageController, app.OnlineController, app.ContactManageController, jwtAuth)
+	admin.RegisterRoutes(engine, app.UserManageController, app.OnlineController, app.ContactManageController, app.GroupManageController, jwtAuth)
 	wsApp.RegisterRoutes(engine, app.WSHandler)
 	contact.RegisterRoutes(engine, app.ContactController, jwtAuth)
 	imApp.RegisterRoutes(engine, app.IMController, jwtAuth)
+	fileApp.RegisterRoutes(engine, app.FileController, jwtAuth)
+	groupApp.RegisterRoutes(engine, app.GroupController, jwtAuth)

 	// [未来] meeting.RegisterRoutes(engine, app.MeetingController, jwtAuth)
 	// [未来] notify.RegisterRoutes(engine, app.NotifyController, jwtAuth)