fix: 修复微信/富友支付回调配置加载错误

- WechatPayCallback 移除对永远为 nil 的单例 wechatPayment 的依赖，
  改为动态按 payment_config_id 加载创建订单时所用的精确配置
- PaymentV2Service 新增 VerifyCallback()（v2 XML 验签）和 PeekOrderNo()（不验签预解析）
- FuiouPayCallback 由 GetActiveConfig 改为 GetConfigForCallback，
  通过 ParseNotify 预解析订单号后精确加载配置，防止切换配置后旧订单验签失败
- wechat_config.Service 注入 assetRechargeStore/agentRechargeStore，
  新增 GetConfigForCallback()：按订单号前缀查 payment_config_id，
  GetByIDUnscoped 加载配置（含已停用/软删除记录），找不到则回退激活配置
- 修复微信 v2 回调响应格式：从 JSON 改为 XML，避免微信持续重试

internal/handler/callback/payment.go

@@ -16,7 +16,6 @@ import (
 	"github.com/break/junhong_cmp_fiber/pkg/constants"
 	"github.com/break/junhong_cmp_fiber/pkg/errors"
 	"github.com/break/junhong_cmp_fiber/pkg/fuiou"
-	"github.com/break/junhong_cmp_fiber/pkg/response"
 	"github.com/break/junhong_cmp_fiber/pkg/wechat"
 )
 
@@ -28,6 +27,7 @@ type AgentRechargeServiceInterface interface {
 // WechatConfigServiceInterface 支付配置服务接口
 type WechatConfigServiceInterface interface {
 	GetActiveConfig(ctx context.Context) (*model.WechatConfig, error)
+	GetConfigForCallback(ctx context.Context, orderNo string) (*model.WechatConfig, error)
 }
 
 type PaymentHandler struct {
@@ -60,43 +60,84 @@ func NewPaymentHandler(
 // WechatPayCallback 微信支付回调（带签名验证）
 // POST /api/callback/wechat-pay
 func (h *PaymentHandler) WechatPayCallback(c *fiber.Ctx) error {
-	if h.wechatPayment == nil {
+	body := c.Body()
+	ctx := context.Background()
+
+	// 预解析订单号（不验签），用于按 payment_config_id 加载创建订单时所用的配置
+	orderNo, err := wechat.PeekOrderNo(body)
+	if err != nil {
+		h.logger.Error("微信回调：预解析订单号失败", zap.Error(err))
+		return errors.New(errors.CodeWechatCallbackInvalid, "回调数据格式错误")
+	}
+
+	cfg, err := h.wechatConfigService.GetConfigForCallback(ctx, orderNo)
+	if err != nil || cfg == nil {
+		h.logger.Error("微信回调：加载支付配置失败",
+			zap.String("order_no", orderNo),
+			zap.Error(err),
+		)
 		return errors.New(errors.CodeWechatCallbackInvalid, "微信支付服务未配置")
 	}
 
-	var httpReq http.Request
-	fasthttpadaptor.ConvertRequest(c.Context(), &httpReq, true)
-
-	ctx := context.Background()
-	_, err := h.wechatPayment.HandlePaymentNotify(&httpReq, func(result *wechat.PaymentNotifyResult) error {
+	switch cfg.ProviderType {
+	case model.ProviderTypeWechatV2:
+		paymentSvc := wechat.NewPaymentV2Service(cfg.OaAppID, cfg.WxMchID, cfg.WxAPIV2Key, cfg.WxNotifyURL, h.logger)
+		result, err := paymentSvc.VerifyCallback(body)
+		if err != nil {
+			return errors.Wrap(errors.CodeWechatCallbackInvalid, err, "微信 v2 回调验签失败")
+		}
 		if result.TradeState != "SUCCESS" {
-			return nil
+			return h.wechatV2SuccessResponse(c)
+		}
+		if err := h.dispatchWechatCallback(ctx, result.OutTradeNo, result.TransactionID); err != nil {
+			return errors.Wrap(errors.CodeWechatCallbackInvalid, err, "处理微信支付回调失败")
 		}
 
-		// TODO: 按 payment_config_id 加载配置验签（当前留桩，仍用 wechatPayment 单例验签）
-
-		// 按订单号前缀分发
-		outTradeNo := result.OutTradeNo
-		switch {
-		case strings.HasPrefix(outTradeNo, "ORD"):
-			return h.orderService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat)
-		case strings.HasPrefix(outTradeNo, constants.AssetRechargeOrderPrefix):
-			return h.rechargeService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat, result.TransactionID)
-		case strings.HasPrefix(outTradeNo, constants.AgentRechargeOrderPrefix):
-			if h.agentRechargeService != nil {
-				return h.agentRechargeService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat, result.TransactionID)
+	case model.ProviderTypeWechat:
+		if h.wechatPayment == nil {
+			return errors.New(errors.CodeWechatCallbackInvalid, "微信 v3 支付未初始化")
+		}
+		var httpReq http.Request
+		fasthttpadaptor.ConvertRequest(c.Context(), &httpReq, true)
+		_, err := h.wechatPayment.HandlePaymentNotify(&httpReq, func(result *wechat.PaymentNotifyResult) error {
+			if result.TradeState != "SUCCESS" {
+				return nil
 			}
-			return fmt.Errorf("代理充值服务未配置，无法处理订单: %s", outTradeNo)
-		default:
-			return fmt.Errorf("未知订单号前缀: %s", outTradeNo)
+			return h.dispatchWechatCallback(ctx, result.OutTradeNo, result.TransactionID)
+		})
+		if err != nil {
+			return errors.Wrap(errors.CodeWechatCallbackInvalid, err, "处理微信支付回调失败")
 		}
-	})
 
-	if err != nil {
-		return errors.Wrap(errors.CodeWechatCallbackInvalid, err, "处理微信支付回调失败")
+	default:
+		return errors.New(errors.CodeWechatCallbackInvalid, "不支持的支付渠道类型")
 	}
 
-	return response.Success(c, map[string]string{"return_code": "SUCCESS"})
+	return h.wechatV2SuccessResponse(c)
+}
+
+// dispatchWechatCallback 按订单号前缀将支付结果分发到对应业务
+func (h *PaymentHandler) dispatchWechatCallback(ctx context.Context, outTradeNo, transactionID string) error {
+	switch {
+	case strings.HasPrefix(outTradeNo, "ORD"):
+		return h.orderService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat)
+	case strings.HasPrefix(outTradeNo, constants.AssetRechargeOrderPrefix):
+		return h.rechargeService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat, transactionID)
+	case strings.HasPrefix(outTradeNo, constants.AgentRechargeOrderPrefix):
+		if h.agentRechargeService != nil {
+			return h.agentRechargeService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat, transactionID)
+		}
+		return fmt.Errorf("代理充值服务未配置，无法处理订单: %s", outTradeNo)
+	default:
+		return fmt.Errorf("未知订单号前缀: %s", outTradeNo)
+	}
+}
+
+// wechatV2SuccessResponse 返回微信 v2 要求的 XML 格式成功响应
+// v2 API 要求 XML 格式的 return_code=SUCCESS，否则微信会持续重试回调
+func (h *PaymentHandler) wechatV2SuccessResponse(c *fiber.Ctx) error {
+	c.Set("Content-Type", "text/xml; charset=utf-8")
+	return c.SendString(`<xml><return_code><![CDATA[SUCCESS]]></return_code><return_msg><![CDATA[OK]]></return_msg></xml>`)
 }
 
 type AlipayCallbackRequest struct {
@@ -151,20 +192,30 @@ func (h *PaymentHandler) FuiouPayCallback(c *fiber.Ctx) error {
 	ctx := c.UserContext()
 	c.Set("Content-Type", "text/xml; charset=gbk")
 
-	activeConfig, err := h.wechatConfigService.GetActiveConfig(ctx)
-	if err != nil || activeConfig == nil {
-		h.logger.Error("富友回调：加载支付配置失败", zap.Error(err))
+	// 预解析订单号（不验签），用于按 payment_config_id 加载创建订单时所用的配置
+	preNotify, err := fuiou.ParseNotify(body)
+	if err != nil {
+		h.logger.Error("富友回调：预解析失败", zap.Error(err))
+		return c.Send(fuiou.BuildNotifyFailResponse("parse failed"))
+	}
+
+	cfg, err := h.wechatConfigService.GetConfigForCallback(ctx, preNotify.MchntOrderNo)
+	if err != nil || cfg == nil {
+		h.logger.Error("富友回调：加载支付配置失败",
+			zap.String("order_no", preNotify.MchntOrderNo),
+			zap.Error(err),
+		)
 		return c.Send(fuiou.BuildNotifyFailResponse("payment config unavailable"))
 	}
 
 	client, err := fuiou.NewClient(
-		activeConfig.FyInsCd,
-		activeConfig.FyMchntCd,
-		activeConfig.FyTermID,
-		activeConfig.FyAPIURL,
-		activeConfig.FyNotifyURL,
-		activeConfig.FyPrivateKey,
-		activeConfig.FyPublicKey,
+		cfg.FyInsCd,
+		cfg.FyMchntCd,
+		cfg.FyTermID,
+		cfg.FyAPIURL,
+		cfg.FyNotifyURL,
+		cfg.FyPrivateKey,
+		cfg.FyPublicKey,
 		h.logger,
 	)
 	if err != nil {