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>

initialize/migrate/database/02123_withdrawal_method.down.sql

@@ -0,0 +1,4 @@
+ALTER TABLE `withdrawals`
+  DROP COLUMN `qr_code_url`,
+  DROP COLUMN `account`,
+  DROP COLUMN `method`;

initialize/migrate/database/02123_withdrawal_method.up.sql

@@ -0,0 +1,4 @@
+ALTER TABLE `withdrawals`
+  ADD COLUMN `method`      TINYINT(1)   NOT NULL DEFAULT 0 COMMENT '收款方式 0:其他 1:支付宝 2:微信 3:银行卡' AFTER `content`,
+  ADD COLUMN `account`     VARCHAR(255) NOT NULL DEFAULT '' COMMENT '收款账号' AFTER `method`,
+  ADD COLUMN `qr_code_url` VARCHAR(500) NOT NULL DEFAULT '' COMMENT '收款码图片URL' AFTER `account`;