feat(admin): 管理端在线监控 + 好友关系管理后端

- admin/service/online_service.go: 在线用户列表/计数
- admin/controller/online_controller.go: GET /admin/online/users|count
- admin/service/contact_manage_service.go: 好友关系分页查询/管理员删除
- admin/controller/contact_manage_controller.go: GET|DELETE /admin/contacts
- 更新 admin router/provider/wire 集成新控制器

Made-with: Cursor

backend/go-service/app/admin/controller/online_controller.go

@@ -0,0 +1,37 @@
+package controller
+
+import (
+	"github.com/echochat/backend/app/admin/service"
+	"github.com/echochat/backend/pkg/utils"
+	"github.com/gin-gonic/gin"
+)
+
+type OnlineController struct {
+	onlineManageService *service.OnlineManageService
+}
+
+func NewOnlineController(onlineManageService *service.OnlineManageService) *OnlineController {
+	return &OnlineController{onlineManageService: onlineManageService}
+}
+
+// GetOnlineUsers GET /api/v1/admin/online/users
+func (ctl *OnlineController) GetOnlineUsers(c *gin.Context) {
+	ctx := c.Request.Context()
+	userIDs, err := ctl.onlineManageService.GetOnlineUsers(ctx)
+	if err != nil {
+		utils.ResponseError(c, "获取在线用户列表失败")
+		return
+	}
+	utils.ResponseOK(c, userIDs)
+}
+
+// GetOnlineCount GET /api/v1/admin/online/count
+func (ctl *OnlineController) GetOnlineCount(c *gin.Context) {
+	ctx := c.Request.Context()
+	count, err := ctl.onlineManageService.GetOnlineCount(ctx)
+	if err != nil {
+		utils.ResponseError(c, "获取在线用户数失败")
+		return
+	}
+	utils.ResponseOK(c, gin.H{"count": count})
+}