feat: 企业微信 Phase 1 — token 续期 + 回调验证 + 调度器注册

wecom.py:
- Token 自动续期 (7200s 过期 + 60s 提前量 + 42001 重试)
- POST 请求自动重试 (最多 3 次，含速率限制退避)
- 新增 send_markdown_message() / send_template_card() 富消息方法

wecom.py API:
- GET /api/wecom/callback: 企微回调 URL 验证 (SHA1 签名 + AES 解密)
- POST /api/wecom/callback: 事件接收占位

scheduler.py:
- 仅推送给已绑定 wecom_userid 的经理
- 消息内容优化 (已填报/未填报人数统计)

main.py:
- APScheduler 注册每日 17:30 自动检查填报

已验证: WECOM_TOKEN 获取成功

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/main.py

@@ -1,11 +1,21 @@
 from contextlib import asynccontextmanager
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from apscheduler.schedulers.asyncio import AsyncIOScheduler
 from app.config import settings
-from app.database import engine, Base
+from app.database import engine, Base, async_session
 from app.api import router as api_router
 from app.api import auth, users, customers, visits, work_plans, mini_business, key_visits
 from app.api import dashboard, upload, export, import_data, wecom, daily_notes, ai_summary
+from app.services.scheduler import check_daily_reporting
+
+_scheduler = AsyncIOScheduler()
+
+
+async def _scheduled_check():
+    """Wrapper for APScheduler: create a fresh session and run the daily check."""
+    async with async_session() as db:
+        await check_daily_reporting(db)
 
 
 @asynccontextmanager
@@ -28,8 +38,15 @@ async def lifespan(app: FastAPI):
             await conn.run_sync(lambda c, t=tbl: c.exec_driver_sql(
                 f"ALTER TABLE {t} ADD COLUMN IF NOT EXISTS edit_log JSONB DEFAULT '[]'"
             ))
+
+    # Start daily reporting scheduler (17:30 CST = 09:30 UTC)
+    _scheduler.add_job(_scheduled_check, "cron", hour=17, minute=30, id="daily_check")
+    _scheduler.start()
+
     yield
+
     # Shutdown
+    _scheduler.shutdown(wait=False)
     await engine.dispose()