fix(m3): code-review 15 项修复（13 项落地，2 项依赖分摊语义记待办）

- 审批：删 _flush_order 撞键内部重试（rollback 会回掉同事务业务行造成
  静默丢数据，异常改由 create 外层重试整体重来/update 路径审计收敛）；
  act() 出参固化前置到 commit 之前（commit 后查询失败会把已通过的审批
  记成失败审计）；驳回/撤回清空方案生效行（防被否决方案进 M3 快照）；
  keyword 改 contains(autoescape=True) 对齐全库转义口径；撤单抽
  withdraw_pending_orders 供编辑清空方案时显式调用
- 业务：删业务遇在途审批单禁删 400、终态审批单随 _hard_delete 清理；
  编辑清空方案同步撤回在途单；历史离职参与人编辑放行（冗余姓名固化
  语义，仅新增参与人做在职校验）
- 迁移：business_secondary_allocations 补 uk(business_id, personnel_id)
  （模型/迁移 py/导出 SQL/init-dev 四方同步，开发库往返重放验证）
- 设置：upload_logo 改同步 def（阻塞操作不卡事件循环）+ file.size 先拦；
  company_name schema 剥空白防全空白入库；logo 旧文件清理移到 commit
  成功后（防库指旧路径而文件已删断链）；uploadLogo 走 request() 解包
  （原直发 service.post 不解包信封，logoUrl 会被置 undefined）
- 备份：restore_drill --drop-exec 先清全部历史 drill 库再演练并即删本轮
  （原语义永远删错对象，每轮净增一份整库拷贝）
- 测试：conftest 清理补 system_settings 种子行与 uploads/logo 文件；
  新增 5 例（驳回清方案/清空撤单/在途禁删终态随删/离职放行/BOOL 边界）；
  全量回归 701 passed
- 遗留 2 项记 AI_CONTEXT（方案版本承载、审批单快照，依赖 ④ 分摊语义）

Co-Authored-By: Claude Code <noreply@anthropic.com>

db/init/init-dev.sql

@@ -734,6 +734,7 @@ CREATE TABLE business_secondary_allocations (
     create_time DATETIME NOT NULL COMMENT '创建时间' DEFAULT CURRENT_TIMESTAMP,
     update_time DATETIME NOT NULL COMMENT '更新时间' DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
     CONSTRAINT pk_business_secondary_allocations PRIMARY KEY (id),
+    CONSTRAINT uk_business_secondary_allocations_business_personnel UNIQUE (business_id, personnel_id),
     CONSTRAINT fk_business_secondary_allocations_business_id FOREIGN KEY(business_id) REFERENCES businesses (id) ON DELETE CASCADE,
     CONSTRAINT fk_business_secondary_allocations_personnel_id FOREIGN KEY(personnel_id) REFERENCES personnel (id) ON DELETE RESTRICT
 )CHARSET=utf8mb4 ENGINE=InnoDB COMMENT='业务二次分配方案明细表（合同建立时录入；比例不要求合计满额，余额归属待澄清）' COLLATE utf8mb4_general_ci;

db/migration/V6__add_settings_allocations_approvals.sql

@@ -53,7 +53,8 @@ CREATE TABLE business_secondary_allocations (
     update_time DATETIME NOT NULL COMMENT '更新时间' DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
     CONSTRAINT pk_business_secondary_allocations PRIMARY KEY (id), 
     CONSTRAINT fk_business_secondary_allocations_business_id FOREIGN KEY(business_id) REFERENCES businesses (id) ON DELETE CASCADE, 
-    CONSTRAINT fk_business_secondary_allocations_personnel_id FOREIGN KEY(personnel_id) REFERENCES personnel (id) ON DELETE RESTRICT
+    CONSTRAINT fk_business_secondary_allocations_personnel_id FOREIGN KEY(personnel_id) REFERENCES personnel (id) ON DELETE RESTRICT, 
+    CONSTRAINT uk_business_secondary_allocations_business_personnel UNIQUE (business_id, personnel_id)
 )CHARSET=utf8mb4 ENGINE=InnoDB COMMENT='业务二次分配方案明细表（合同建立时录入；比例不要求合计满额，余额归属待澄清）' COLLATE utf8mb4_general_ci;
 
 CREATE INDEX idx_business_secondary_allocations_business_id ON business_secondary_allocations (business_id);