Add per-config id lock to reload and remove stale comment

app/fanout/manager.py

@@ -11,7 +11,7 @@ from app.fanout.base import FanoutModule
 logger = logging.getLogger(__name__)
 _DISPATCH_TIMEOUT_SECONDS = 30.0
 
-# Type string -> module class mapping (extended in Phase 2/3)
+# Type string -> module class mapping
 _MODULE_TYPES: dict[str, type] = {}
 
 
@@ -122,14 +122,16 @@ class FanoutManager:
 
     async def reload_config(self, config_id: str) -> None:
         """Stop old module (if any) and start updated config."""
-        await self.remove_config(config_id)
+        lock = self._restart_locks.setdefault(config_id, asyncio.Lock())
+        async with lock:
+            await self.remove_config(config_id)
 
-        from app.repository.fanout import FanoutConfigRepository
+            from app.repository.fanout import FanoutConfigRepository
 
-        cfg = await FanoutConfigRepository.get(config_id)
-        if cfg is None or not cfg["enabled"]:
-            return
-        await self._start_module(cfg)
+            cfg = await FanoutConfigRepository.get(config_id)
+            if cfg is None or not cfg["enabled"]:
+                return
+            await self._start_module(cfg)
 
     async def remove_config(self, config_id: str) -> None:
         """Stop and remove a module."""
@@ -140,7 +142,6 @@ class FanoutManager:
                 await module.stop()
             except Exception:
                 logger.exception("Error stopping fanout module %s", config_id)
-        self._restart_locks.pop(config_id, None)
 
     async def _dispatch_matching(
         self,