F1: add reusable task backend resources and migrate task tools

backend/routes/tools.py

@@ -100,7 +100,7 @@ def _payload(
     _normalize_http_template_inputs(definition)
     secrets = (
         merge_secrets(body.secrets, stored_secrets or {})
-        if definition["type"] in {"http", "task"}
+        if definition["type"] == "http"
         else {}
     )
     secret_variables = (secrets.get("dynamic_variables") or {}) if secrets else {}
@@ -154,7 +154,7 @@ async def list_tools(session: AsyncSession = Depends(get_session)):
     rows = (
         await session.execute(
             select(Tool)
-            .where(Tool.type.in_(("http", "mcp", "client", "task")))
+            .where(Tool.type.in_(("http", "mcp", "client")))
             .order_by(Tool.updated_at.desc())
         )
     ).scalars().all()