fix(agent): acquire per-session lock in process_direct (#4080)

nanobot/agent/loop.py

@@ -1667,7 +1667,10 @@ class AgentLoop:
             channel=channel, sender_id="user", chat_id=chat_id,
             content=content, media=media or [],
         )
+        # Share the dispatch lock so direct calls serialize with bus turns.
+        lock = self._session_locks.setdefault(session_key, asyncio.Lock())
         try:
+            async with lock:
                 return await self._process_message(
                     msg,
                     session_key=session_key,

tests/test_openai_api.py

@@ -406,6 +406,7 @@ async def test_process_direct_accepts_media() -> None:
 
     loop = AgentLoop.__new__(AgentLoop)
     loop._connect_mcp = AsyncMock()
+    loop._session_locks = {}
 
     captured_msg = None