feat(contact): Controller、Router 与 Wire 集成

- controller/contact_controller.go: 全部 17 个 REST API 端点处理器
- router.go: Contact 模块路由注册（JWT 中间件保护）
- provider.go: Wire Provider Set（DAO + Service + Controller）
- 更新全局 provider、wire.go、router.go 集成 Contact 模块

Made-with: Cursor

backend/go-service/app/provider/wire.go

@@ -6,6 +6,7 @@ package provider
 import (
 	"github.com/echochat/backend/app/admin"
 	"github.com/echochat/backend/app/auth"
+	"github.com/echochat/backend/app/contact"
 	wsApp "github.com/echochat/backend/app/ws"
 	"github.com/echochat/backend/config"
 	"github.com/google/wire"
@@ -18,6 +19,7 @@ func InitializeApp(cfg *config.Config) (*App, error) {
 		auth.AuthSet,
 		admin.AdminSet,
 		wsApp.WSSet,
+		contact.ContactSet,
 	)
 	return nil, nil
 }