```

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/observability/service.py

@@ -0,0 +1,114 @@
+from typing import Any
+
+from sqlalchemy import text
+from sqlalchemy.orm import Session
+
+from app.core.config import get_settings
+from app.modules.events.constants import EventStatus
+from app.modules.events.service import EventService
+from app.modules.observability.constants import (
+    ObservabilityKey,
+    ObservabilityMetricKey,
+    ObservabilityStatus,
+)
+from app.modules.workflows.constants import WorkflowStatus
+from app.modules.workflows.service import WorkflowService
+from app.modules.writebacks.constants import WritebackStatus
+from app.modules.writebacks.service import WritebackService
+
+
+class ObservabilityService:
+    """Build health, readiness, and JSON metrics for V3 operations."""
+
+    def __init__(self, db: Session):
+        self.db = db
+
+    def live(self) -> dict[str, str]:
+        return {ObservabilityKey.STATUS: ObservabilityStatus.OK}
+
+    def ready(self) -> dict[str, Any]:
+        checks = {
+            ObservabilityKey.DATABASE: self._database_check(),
+            ObservabilityKey.REDIS: self._redis_check(),
+            ObservabilityKey.EVENTS: self._events_check(),
+            ObservabilityKey.WORKFLOWS: self._workflows_check(),
+            ObservabilityKey.WRITEBACKS: self._writebacks_check(),
+        }
+        degraded = any(
+            item[ObservabilityKey.STATUS]
+            in {ObservabilityStatus.DEGRADED, ObservabilityStatus.ERROR}
+            for item in checks.values()
+        )
+        return {
+            ObservabilityKey.STATUS: (
+                ObservabilityStatus.DEGRADED if degraded else ObservabilityStatus.OK
+            ),
+            ObservabilityKey.CHECKS: checks,
+        }
+
+    def metrics(self) -> dict[str, Any]:
+        return {
+            ObservabilityKey.METRICS: {
+                ObservabilityKey.EVENTS: EventService(self.db).count_by_status(),
+                ObservabilityKey.WORKFLOWS: WorkflowService(self.db).count_by_status(),
+                ObservabilityKey.WRITEBACKS: WritebackService(self.db).count_by_status(),
+            }
+        }
+
+    def _database_check(self) -> dict[str, Any]:
+        try:
+            self.db.execute(text("select 1")).scalar()
+        except Exception as exc:
+            return {
+                ObservabilityKey.STATUS: ObservabilityStatus.ERROR,
+                ObservabilityMetricKey.ERROR: str(exc),
+            }
+        return {ObservabilityKey.STATUS: ObservabilityStatus.OK}
+
+    def _redis_check(self) -> dict[str, Any]:
+        settings = get_settings()
+        if not settings.task_queue_enabled:
+            return {ObservabilityKey.STATUS: ObservabilityStatus.SKIPPED}
+        try:
+            from redis import Redis
+
+            Redis.from_url(settings.redis_url, socket_connect_timeout=1).ping()
+        except Exception as exc:
+            return {
+                ObservabilityKey.STATUS: ObservabilityStatus.DEGRADED,
+                ObservabilityMetricKey.ERROR: str(exc),
+            }
+        return {ObservabilityKey.STATUS: ObservabilityStatus.OK}
+
+    def _events_check(self) -> dict[str, Any]:
+        counts = EventService(self.db).count_by_status()
+        failed = counts.get(EventStatus.FAILED, 0)
+        return {
+            ObservabilityKey.STATUS: (
+                ObservabilityStatus.DEGRADED if failed else ObservabilityStatus.OK
+            ),
+            ObservabilityMetricKey.PENDING: counts.get(EventStatus.PENDING, 0),
+            ObservabilityMetricKey.FAILED: failed,
+        }
+
+    def _workflows_check(self) -> dict[str, Any]:
+        counts = WorkflowService(self.db).count_by_status()
+        failed = counts.get(WorkflowStatus.FAILED, 0)
+        return {
+            ObservabilityKey.STATUS: (
+                ObservabilityStatus.DEGRADED if failed else ObservabilityStatus.OK
+            ),
+            ObservabilityMetricKey.RUNNING: counts.get(WorkflowStatus.RUNNING, 0),
+            ObservabilityMetricKey.FAILED: failed,
+        }
+
+    def _writebacks_check(self) -> dict[str, Any]:
+        counts = WritebackService(self.db).count_by_status()
+        failed = counts.get(WritebackStatus.FAILED, 0)
+        return {
+            ObservabilityKey.STATUS: (
+                ObservabilityStatus.DEGRADED if failed else ObservabilityStatus.OK
+            ),
+            ObservabilityMetricKey.DISABLED: counts.get(WritebackStatus.DISABLED, 0),
+            ObservabilityMetricKey.FAILED: failed,
+        }