```

feat: 添加数据库迁移脚本并更新Dockerfile配置

- 在Dockerfile中添加alembic配置文件和目录的复制指令
- 更新alembic/env.py注册新的模块模型：events、workflows、writebacks
- 生成完整的初始数据库schema迁移脚本，包含以下表：
  - approval_requests, attendance_records, audit_logs, domain_events
  - expenses, feishu_event_receipts, fund_accounts, legacy_sync_runs
  - official_writeback_runs, performance_metrics, policies, procurements
  - projects, report_push_runs, risk_event_actions, risk_events
  - standards, suppliers, work_reports, work_tasks, workflow_actions
  - workflow_instances等21个数据表结构定义
- 在API路由器中添加新模块的路由：events、workflows、writebacks、observability
```

app/main.py

@@ -3,6 +3,7 @@ from fastapi.middleware.cors import CORSMiddleware
 
 from app.api.router import api_router
 from app.core.config import get_settings
+from app.core.middleware import request_id_middleware
 from app.core.scheduler import attach_scheduler
 
 
@@ -24,6 +25,7 @@ def create_app() -> FastAPI:
         ),
     )
 
+    app.middleware("http")(request_id_middleware)
     app.add_middleware(
         CORSMiddleware,
         allow_origins=settings.cors_origins,