feat(trade): implement second-hand trading/flea market feature

Add complete trade functionality including:
- TradeItem, TradeImage, TradeFavorite models with auto-migration
- TradeRepository with CRUD and favorite operations
- TradeService with business logic for listing, creating, updating, status management
- TradeHandler with RESTful endpoints for trade operations
- DTOs and converters for request/response handling

Routes include: list, get by id, create, update, delete, status update, view recording, favorite/unfavorite.

internal/wire/handler.go

@@ -34,6 +34,7 @@ var HandlerSet = wire.NewSet(
 	handler.NewVerificationHandler,
 	handler.NewAdminProfileAuditHandler,
 	handler.NewPostHandler,
+	handler.NewTradeHandler,
 
 	// 需要特殊处理的 Handler
 	ProvideUserHandler,

internal/wire/repository.go

@@ -46,6 +46,9 @@ var RepositorySet = wire.NewSet(
 
 	// 帖子内链引用关系
 	repository.NewPostRefRepository,
+
+	// 二手交易相关
+	repository.NewTradeRepository,
 )
 
 // ProvideUserActivityRepository 提供用户活跃数据仓储

internal/wire/service.go

@@ -68,6 +68,9 @@ var ServiceSet = wire.NewSet(
 	// 帖子内链引用
 	ProvidePostRefService,
 
+	// 二手交易
+	ProvideTradeService,
+
 	// 日志服务
 	ProvideAsyncLogManager,
 	ProvideOperationLogService,
@@ -496,3 +499,7 @@ func ProvidePostRefService(
 ) service.PostRefService {
 	return service.NewPostRefService(refRepo, postRepo)
 }
+
+func ProvideTradeService(tradeRepo repository.TradeRepository) service.TradeService {
+	return service.NewTradeService(tradeRepo)
+}