修复：防止提现创建中的竞态条件和重复收益

- 在 earnings_line 表添加唯一约束 (tenant_id, order_id, clerk_id, earning_type, deleted)
- 重排提现创建流程：先预留收益行，成功后才创建提现请求
- 在收益行预留时添加状态验证，检测并发修改
- 使用临时提现ID进行预留，创建请求后替换为真实ID
- 添加唯一约束前先清理重复的收益记录（V10 迁移）

此修复解决了关键的竞态条件问题：并发提现可能创建没有资金支持的孤儿请求记录。
修复后确保快速失败行为 - 如果收益行已被占用，提现请求永远不会被创建。

play-admin/src/main/resources/db/migration/V10__dedupe_and_unique_earnings_line.sql

@@ -0,0 +1,18 @@
+-- Remove duplicate earnings lines per tenant/order/clerk/type and add unique constraint
+
+DELETE FROM `play_earnings_line`
+WHERE `id` IN (
+    SELECT dup_id FROM (
+        SELECT id AS dup_id,
+               ROW_NUMBER() OVER (
+                   PARTITION BY tenant_id, order_id, clerk_id, earning_type
+                   ORDER BY created_time, id
+               ) AS rn
+        FROM `play_earnings_line`
+        WHERE deleted = 0
+    ) ranked
+    WHERE ranked.rn > 1
+);
+
+ALTER TABLE `play_earnings_line`
+    ADD UNIQUE KEY `uk_tenant_order_clerk_type` (`tenant_id`, `order_id`, `clerk_id`, `earning_type`, `deleted`);