```

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/core/middleware.py

@@ -0,0 +1,18 @@
+import uuid
+from collections.abc import Callable
+
+from fastapi import Request, Response
+
+from app.core.constants import HttpHeader
+from app.core.request_context import reset_request_id, set_request_id
+
+
+async def request_id_middleware(request: Request, call_next: Callable) -> Response:
+    request_id = request.headers.get(HttpHeader.X_REQUEST_ID) or uuid.uuid4().hex
+    token = set_request_id(request_id)
+    try:
+        response = await call_next(request)
+        response.headers[HttpHeader.X_REQUEST_ID] = request_id
+        return response
+    finally:
+        reset_request_id(token)