新功能(#41): 提现优化 — 收款方式选择 + 取消提现 + 收款码上传

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

internal/model/user/withdrawal_const.go

@@ -0,0 +1,15 @@
+package user
+
+const (
+	WithdrawalStatusPending   uint8 = 0 // 待审核
+	WithdrawalStatusApproved  uint8 = 1 // 已通过
+	WithdrawalStatusRejected  uint8 = 2 // 已拒绝
+	WithdrawalStatusCancelled uint8 = 3 // 已取消（用户自行撤回）
+)
+
+const (
+	WithdrawalMethodOther  uint8 = 0 // 其他
+	WithdrawalMethodAlipay uint8 = 1 // 支付宝
+	WithdrawalMethodWechat uint8 = 2 // 微信
+	WithdrawalMethodBank   uint8 = 3 // 银行卡
+)