feat: 添加中国节假日感知定时功能

- 新增 chinese_holidays 表，通过 timor.tech API 同步节假日数据
- 修正 holiday 字段解读：holiday=true → 休息日，holiday=false → 调休工作日
- 工作日 8:00-22:00 每小时爬取，周末/节假日/夜间自动跳过
- 新增 /api/v1/holidays/sync 和 /api/v1/holidays/today 接口
- 企微菜单新增「同步节假日」按钮，支持手动触发同步

app/api/holidays.py

@@ -0,0 +1,30 @@
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.api.deps import get_db
+from app.services.holiday_service import now_in_china, sync_holidays
+
+router = APIRouter()
+
+
+@router.post("/holidays/sync")
+async def sync_holidays_endpoint(
+    year: int | None = Query(None, description="同步年份，默认当前年份"),
+    db: AsyncSession = Depends(get_db),
+):
+    if year is None:
+        year = now_in_china().year
+    count = await sync_holidays(db, year)
+    return {"status": "ok", "year": year, "synced": count}
+
+
+@router.get("/holidays/today")
+async def get_today_status(db: AsyncSession = Depends(get_db)):
+    from app.services.holiday_service import is_workday
+    today = now_in_china()
+    workday = await is_workday(db, today)
+    return {
+        "date": today.isoformat(),
+        "is_workday": workday,
+        "message": "工作日，正常爬取" if workday else "非工作日，跳过爬取",
+    }