refactor(system): 重构消息中心功能

- 移除 WebSocket相关代码
- 新增 SSE (Server-Sent Events) 实现消息推送
- 优化消息中心未读数量展示和更新逻辑- 调整消息中心相关 API 和前端展示

backend/application/asgi.py

@@ -8,9 +8,7 @@ https://docs.djangoproject.com/en/3.2/howto/deployment/asgi/
 """
 
 import os
-from channels.auth import AuthMiddlewareStack
-from channels.security.websocket import AllowedHostsOriginValidator
-from channels.routing import ProtocolTypeRouter, URLRouter
+from channels.routing import ProtocolTypeRouter
 from django.core.asgi import get_asgi_application
 
 os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'application.settings')
@@ -18,15 +16,6 @@ os.environ["DJANGO_ALLOW_ASYNC_UNSAFE"] = "true"
 
 http_application = get_asgi_application()
 
-from application.routing import websocket_urlpatterns
-
 application = ProtocolTypeRouter({
     "http": http_application,
-    'websocket': AllowedHostsOriginValidator(
-        AuthMiddlewareStack(
-            URLRouter(
-                websocket_urlpatterns  # 指明路由文件是devops/routing.py
-            )
-        )
-    ),
 })