```

refactor: 移除审批和回写功能模块

移除了整个审批(approvals)和官方回写(writebacks)功能模块，
包括相关模型、路由、服务和配置项。更新了数据库迁移文件，
删除了相关的审批请求表和官方回写运行表。同时从API路由器中
移除了相应的路由，并调整了安全常量和字段验证器以匹配变更。
```

app/modules/reports/routes.py

@@ -4,6 +4,7 @@ from fastapi import APIRouter, Depends
 from sqlalchemy.orm import Session
 
 from app.core.database import get_db
+from app.core.operation_guard import require_operations_enabled
 from app.core.security import ApiPrincipal, require_api_key
 from app.core.task_queue import enqueue_daily_brief_push, enqueue_project_weekly_push
 from app.modules.reports.schemas import (
@@ -82,6 +83,8 @@ def generate_work_report(
     db: Session = Depends(get_db),
     principal: ApiPrincipal = Depends(require_api_key),
 ) -> dict:
+    if payload.persist:
+        require_operations_enabled()
     return ReportService(db).generate_work_report(
         report_type=payload.report_type,
         reporter=payload.reporter,

app/modules/reports/schemas.py

@@ -26,5 +26,5 @@ class WorkReportGenerateRequest(BaseModel):
     project_code: str | None = None
     period_start: date | None = None
     period_end: date | None = None
-    persist: bool = True
+    persist: bool = False
     actor: str = ActorValue.API