feat: 富消息升级 — 催办用模板卡片 + 公告用 Markdown

scheduler.py:
- 未填报经理 → 模板卡片消息(标题+描述+「去填报」按钮)
- 支局长/领导 → Markdown 每日填报汇总(markdown)
- 文本消息作为降级方案

wecom.py API:
- remind: 模板卡片优先 → 降级文本
- announcement: Markdown 优先 → 降级文本

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

backend/app/api/wecom.py

@@ -201,9 +201,17 @@ async def send_reminder(
     wecom_ids = [r[0] for r in result.all() if r[0]]
 
     content = data.message or "📋 请及时完成今日拜访记录填报。"
-    success = await wecom_client.send_text_message(wecom_ids, content)
+    success = await wecom_client.send_template_card(
+        user_ids=wecom_ids,
+        title="📋 填报提醒",
+        desc=content,
+        url="https://qj.dhdx.fun/m",
+        btn_text="去填报",
+    )
+    if not success:
+        success = await wecom_client.send_text_message(wecom_ids, content)
 
-    return {"success": success, "sent_to": len(wecom_ids)}
+    return {"success": success, "sent_to": len(wecom_ids), "rich": True}
 
 
 @router.post("/announcement")
@@ -212,14 +220,16 @@ async def send_announcement(
     current_user: dict = Depends(require_director),
     db: AsyncSession = Depends(get_db),
 ):
-    """Director sends an announcement to all team members."""
+    """Director sends an announcement to all team members (markdown)."""
     result = await db.execute(select(User.wecom_userid).where(User.wecom_userid.isnot(None)))
     wecom_ids = [r[0] for r in result.all()]
 
-    content = f"📢 支局长公告\n\n{data.content}"
-    success = await wecom_client.send_text_message(wecom_ids, content)
+    markdown = f"## 📢 支局长公告\n\n{data.content}"
+    success = await wecom_client.send_markdown_message(markdown)
+    if not success:
+        success = await wecom_client.send_text_message(wecom_ids, f"📢 支局长公告\n\n{data.content}")
 
-    return {"success": success, "sent_to": len(wecom_ids)}
+    return {"success": success, "sent_to": len(wecom_ids), "rich": True}
 
 
 @router.post("/test-message")