```

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/modules/writebacks/constants.py

@@ -0,0 +1,42 @@
+from enum import StrEnum
+
+
+class WritebackStatus(StrEnum):
+    DRAFT = "draft"
+    PENDING_APPROVAL = "pending_approval"
+    DISABLED = "disabled"
+    QUEUED = "queued"
+    SENT = "sent"
+    FAILED = "failed"
+
+
+class WritebackActionValue(StrEnum):
+    WRITEBACK = "writeback"
+
+
+class WritebackPayloadKey(StrEnum):
+    CODE = "code"
+    STATUS = "status"
+    DOMAIN = "domain"
+    RECORD_ID = "record_id"
+    ACTION = "action"
+    PAYLOAD = "payload"
+    APPROVAL_TICKET_ID = "approval_ticket_id"
+    PROVIDER_RESPONSE = "provider_response"
+    ERROR_MESSAGE = "error_message"
+
+
+class WritebackResponseKey(StrEnum):
+    ITEMS = "items"
+    DATA = "data"
+
+
+class WritebackErrorDetail(StrEnum):
+    RUN_NOT_FOUND = "Writeback run not found"
+    APPROVAL_TICKET_REQUIRED = "approval_ticket_id is required for official writeback"
+    OFFICIAL_API_NOT_CONFIGURED = "Official API is not configured"
+
+
+WRITEBACK_CODE_PREFIX = "WB"
+WRITEBACK_DISABLED_MESSAGE = "Official writeback is disabled"
+WRITEBACK_DEFAULT_ACTION = "sync"