fix: resolve Feishu cross-app notification routing bug

Implement per-app open_id storage via user_feishu_open_ids table with
union_id-based cross-app user identification. WS handlers now auto-capture
open_id+union_id and resolve/associate user accounts. Schedule notifications
route through the correct bot's open_id instead of always falling back to 苹果.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/api/feishu_bind.py

@@ -89,9 +89,16 @@ async def bind_feishu(
     if not data.open_id or not data.open_id.strip():
         raise HTTPException(status_code=400, detail="open_id 不能为空")
 
-    current_user.feishu_open_id = data.open_id.strip()
+    open_id = data.open_id.strip()
+    current_user.feishu_open_id = open_id
     db.commit()
-    logger.info("飞书绑定成功: user=%s open_id=%s", current_user.id, data.open_id)
+    # 同步写入多应用 open_id 表（含 union_id 用于跨应用识别）
+    from app.services.feishu_open_id_service import save_open_id
+    from app.services.feishu_app_service import lookup_union_id_by_open_id
+    from app.core.config import settings
+    union_id = lookup_union_id_by_open_id(open_id)
+    save_open_id(db, app_id=settings.FEISHU_APP_ID or "", open_id=open_id, user_id=current_user.id, union_id=union_id)
+    logger.info("飞书绑定成功: user=%s open_id=%s union_id=%s", current_user.id, open_id, union_id)
     return {"message": "飞书账号绑定成功"}
 
 
@@ -132,7 +139,13 @@ async def lookup_and_bind(
 
     current_user.feishu_open_id = open_id
     db.commit()
-    logger.info("飞书自动绑定成功: user=%s email=%s open_id=%s", current_user.id, current_user.email, open_id)
+    # 同步写入多应用 open_id 表（含 union_id 用于跨应用识别）
+    from app.services.feishu_open_id_service import save_open_id
+    from app.services.feishu_app_service import lookup_union_id_by_open_id
+    from app.core.config import settings
+    union_id = lookup_union_id_by_open_id(open_id)
+    save_open_id(db, app_id=settings.FEISHU_APP_ID or "", open_id=open_id, user_id=current_user.id, union_id=union_id)
+    logger.info("飞书自动绑定成功: user=%s email=%s open_id=%s union_id=%s", current_user.id, current_user.email, open_id, union_id)
 
     # 发送测试消息
     from app.services.feishu_app_service import send_message_to_user
@@ -176,6 +189,12 @@ async def bind_pending(
     open_id = ids[-1]
     current_user.feishu_open_id = open_id
     db.commit()
+    # 同步写入多应用 open_id 表（含 union_id 用于跨应用识别）
+    from app.services.feishu_open_id_service import save_open_id
+    from app.services.feishu_app_service import lookup_union_id_by_open_id
+    from app.core.config import settings
+    union_id = lookup_union_id_by_open_id(open_id)
+    save_open_id(db, app_id=settings.FEISHU_APP_ID or "", open_id=open_id, user_id=current_user.id, union_id=union_id)
     clear_pending_open_ids()
 
     logger.info("飞书事件绑定成功: user=%s open_id=%s", current_user.id, open_id)