fix(tasks): isolate worker execution scopes

Persist a required Server-owned execution scope and enforce it for listing, claiming, lease recovery and SCADA verification. Backfill existing tasks explicitly through migration 034 so local development workers no longer claim production tasks from the shared database.

app/mcp/query_service.py

@@ -12,6 +12,7 @@ from datetime import datetime, timezone
 from uuid import uuid4
 from fastapi import HTTPException
 from fastapi.encoders import jsonable_encoder
+from app.core.config import settings
 from app.auth.permissions import permissions_for_context
 from app.infra.db.postgresql import read_queries as reads
 from app.infra.db.postgresql.spatial_queries import nearby_elements
@@ -52,6 +53,7 @@ def task_service(scope: QueryScope) -> OperationalTaskService:
         OperationalTaskRepository(scope.connection, scope.project.project_id),
         scope.project,
         set(permissions_for_context(scope.project)),
+        execution_scope=settings.operational_task_execution_scope,
     )