fix: harden realtime pipeline lifecycle

backend/services/config_resolver.py

@@ -34,7 +34,7 @@ async def _resource_for(
     binding = await session.get(AssistantModelBinding, (assistant_id, capability))
     resource_id = binding.model_resource_id if binding else None
     resource = await session.get(ModelResource, resource_id) if resource_id else None
-    if resource and resource.capability != capability:
+    if resource and (not resource.enabled or resource.capability != capability):
         resource = None
     if resource is None:
         resource = (
@@ -60,6 +60,7 @@ async def _agent_resource_for(
     resource = await session.get(ModelResource, resource_id) if resource_id else None
     if (
         resource
+        and resource.enabled
         and resource.capability == "Agent"
         and resource.interface_type == interface_type
     ):