F1: add reusable task backend resources and migrate task tools

backend/services/config_resolver.py

@@ -22,6 +22,7 @@ from models import (
     RuntimeToolBinding,
 )
 from services.node_specs import copy_graph, graph_references
+from services.task_backend_resources import resolve_task_backend
 from sqlalchemy import or_, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -174,6 +175,7 @@ async def _tools_for(
             .where(
                 or_(*identity_filters),
                 Tool.status == "active",
+                Tool.type.in_(("http", "mcp", "client")),
             )
         )
     ).scalars().all()
@@ -323,6 +325,7 @@ async def resolve_runtime_config(
         built_in_tools=assistant.built_in_tools or {},
         tools=runtime_tools,
         tool_bindings=prompt_tool_bindings,
+        task_backend=await resolve_task_backend(session, assistant),
         knowledge_base_id=assistant.knowledge_base_id,
         knowledge_base_name=knowledge_base.name if knowledge_base else "",
         knowledge_base_description=knowledge_base.description if knowledge_base else "",