feat: implement withdrawal improvements P01-P05

- P04: fix Withdrawal.TableName() to return 'withdrawals'
- P03: add WithdrawalStatus* and WithdrawalMethod* constants; replace magic numbers; add CommissionTypeWithdrawCancel=338
- P01: add POST /v1/public/user/withdrawal_cancel to cancel pending withdrawals with ownership check, row lock, commission refund, and audit log
- P02: add method/account/qr_code_url fields to Withdrawal model and API; add input validation (qr_code_url required for Alipay/Wechat, account required for bank)
- P05: add method filter to admin GET /v1/admin/user/withdrawal/list

Co-authored-by: multica-agent <github@multica.ai>

internal/handler/public/user/cancelWithdrawalHandler.go

@@ -0,0 +1,26 @@
+package user
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/perfect-panel/server/internal/logic/public/user"
+	"github.com/perfect-panel/server/internal/svc"
+	"github.com/perfect-panel/server/internal/types"
+	"github.com/perfect-panel/server/pkg/result"
+)
+
+// Cancel Withdrawal
+func CancelWithdrawalHandler(svcCtx *svc.ServiceContext) func(c *gin.Context) {
+	return func(c *gin.Context) {
+		var req types.CancelWithdrawalRequest
+		_ = c.ShouldBind(&req)
+		validateErr := svcCtx.Validate(&req)
+		if validateErr != nil {
+			result.ParamErrorResult(c, validateErr)
+			return
+		}
+
+		l := user.NewCancelWithdrawalLogic(c.Request.Context(), svcCtx)
+		resp, err := l.CancelWithdrawal(&req)
+		result.HttpResult(c, resp, err)
+	}
+}