feat: 后端接入微信提现人工审核与资金安全校验

提现申请改为先扣款并进入待审核，审核通过后才发起微信打款，审核拒绝或微信失败时自动退款。

新增运营后台提现列表的关键词搜索、日期筛选、快捷筛选和排序参数，并支持批量通过、批量拒绝、批量刷新查单。

新增微信支付配置健康检查、现金账本校验、自动对账 worker 和单实例保护。

新增数据库唯一索引，约束同一用户未完成提现和同一提现单重复退款，提升并发安全性。

app/api/v1/wallet.py

@@ -176,7 +176,7 @@ def withdraw_info(user: CurrentUser, db: DbSession) -> WithdrawInfoOut:
     "/withdraw",
     response_model=WithdrawResultOut,
     summary="发起提现(扣款建单,待人工审核;审核通过后才打款)",
-    dependencies=[Depends(rate_limit(20, 60, "withdraw"))],  # #6 同 IP 每分钟≤20 次
+    dependencies=[Depends(rate_limit(5, 60, "withdraw"))],  # IP 级粗限流;用户级未完成单限制在仓库层
 )
 def withdraw(req: WithdrawRequest, user: CurrentUser, db: DbSession) -> WithdrawResultOut:
     # 提现发起本身不调微信(打款在审核通过后),但仍要求微信支付已配置——否则审核通过也打不了款,提前拦
@@ -189,12 +189,17 @@ def withdraw(req: WithdrawRequest, user: CurrentUser, db: DbSession) -> Withdraw
     except crud_wallet.InvalidWithdrawAmountError as e:
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
-            detail=f"amount_cents must be within [{WITHDRAW_MIN_CENTS}, {WITHDRAW_MAX_CENTS}]",
+            detail="提现金额不符合要求",
         ) from e
     except crud_wallet.WechatNotBoundError as e:
-        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="wechat not bound") from e
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="请先绑定微信") from e
+    except crud_wallet.WithdrawTooFrequentError as e:
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="已有提现申请正在审核或打款中,请处理完成后再申请",
+        ) from e
     except crud_wallet.InsufficientCashError as e:
-        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="insufficient cash balance") from e
+        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="现金余额不足") from e
 
     # 调试直发(非生产):skip_review=true 时跳过人工审核,立即发起微信转账(等价 admin approve)。
     # 双闸保护——客户端仅 debug 包下发此 flag,服务端仅非 prod 才认;任一道闸拦住即恢复正常审核,