refactor: вся фильтрация сообщений на стороне Tracker

- System messages: агенты получают только если @slug в content
- Убрана дублирующая фильтрация из Picogent Router

src/tracker/ws/manager.py

@@ -77,8 +77,18 @@ class ConnectionManager:
                 await self.disconnect(client.session_id)
 
     async def broadcast_message(self, project_id: str, message: dict, author_slug: str):
-        """Broadcast message.new. Humans get everything, agents filtered."""
+        """Broadcast message.new. Humans get everything, agents filtered.
+        
+        Filtering for agents:
+        - Skip own messages (author_slug == client slug)
+        - Skip if not subscribed to project
+        - Skip if chat_listen == "none"
+        - If chat_listen == "mentions": only if @slug in mentions
+        - System messages: only if @slug mentioned in content
+        """
         mentions = message.get("mentions", [])
+        content = message.get("content", "")
+        author_type = message.get("author_type", "")
         payload = {"type": "message.new", "data": message}
 
         for session_id, client in list(self.sessions.items()):
@@ -88,11 +98,18 @@ class ConnectionManager:
             if client.member_type in ("human", "bridge"):
                 await self.send_to_session(session_id, payload)
                 continue
-            # Agents: subscription + chat_listen
+            # Agents: subscription check
             if project_id not in client.subscribed_projects:
                 continue
             if client.chat_listen == "none":
                 continue
+            # System messages: only if agent is mentioned in content
+            if author_type == "system":
+                if f"@{client.member_slug}" not in content:
+                    continue
+                await self.send_to_session(session_id, payload)
+                continue
+            # Regular messages: chat_listen filter
             if client.chat_listen == "mentions" and client.member_slug not in mentions:
                 continue
             await self.send_to_session(session_id, payload)