fix(arch-038,arch-054): register_event_handlers hook in BasePlugin; entity model lookup matches registry shape

app/plugins/base.py

@@ -97,6 +97,15 @@ class BasePlugin(ABC):
         """
         return []
 
+    async def register_event_handlers(self, event_bus: EventBus) -> None:
+        """Register event handlers for the background worker (ARCH-038 hook).
+
+        The worker calls this on every active plugin at startup so plugins
+        can subscribe to events even when the web process is separate.
+        Default: no-op. Override to subscribe handlers.
+        """
+        return None
+
     # ─── Job Modules ───
 
     def get_job_modules(self) -> list[str]:

app/routes/entity_permissions.py

@@ -111,7 +111,7 @@ async def _check_entity_ownership(
             detail={"detail": f"Unknown entity type: {entity_type}", "code": "not_found"},
         )
 
-    model = model_info["model"]
+    model = model_info  # ENTITY_MODELS maps directly to model classes
     try:
         eid = uuid.UUID(entity_id)
     except ValueError: