新功能(#26): 拆分退款日志查询接口

拆分用户中心退款日志查询：

- 新增 GET /v1/public/user/commission_return_log（333/337/338）
- 旧 GET /v1/public/user/withdrawal_log?biz_type=commission_refund 复用新逻辑做兼容
- 默认 withdrawal_log 行为不变（仍查 withdrawals 表）
- 单测覆盖 333/337/338 happy path、坏 JSON 跳过、object_id 隔离、handler 级 HTTP 响应

父 issue: HIF-25
子 issue: HIF-26

internal/handler/routes.go

@@ -1180,6 +1180,9 @@ func RegisterHandlers(router *gin.Engine, serverCtx *svc.ServiceContext) {
 		// Verify Email
 		publicUserGroupRouter.POST("/verify_email", publicUser.VerifyEmailHandler(serverCtx))
 
+		// Query Commission Return Log
+		publicUserGroupRouter.GET("/commission_return_log", publicUser.QueryCommissionReturnLogHandler(serverCtx))
+
 		// Query Withdrawal Log
 		publicUserGroupRouter.GET("/withdrawal_log", publicUser.QueryWithdrawalLogHandler(serverCtx))
 	}