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/services/scada_replay.py

@@ -6,6 +6,7 @@ import json
 from uuid import NAMESPACE_URL, uuid4, uuid5
 
 from fastapi import HTTPException
+from app.core.config import settings
 from app.auth.permissions import permissions_for_context
 
 from app.domain.schemas.project_settings import ScadaMonitoringSettings
@@ -439,7 +440,8 @@ class ScadaReplayService:
         alerts = TaskAlertService(TaskAlertRepository(self.repo.connection, self.context.project_id),
                                   self.context, internal_producer_id=producer)
         tasks = OperationalTaskService(OperationalTaskRepository(self.repo.connection, self.context.project_id),
-                                       self.context, permissions_for_context(self.context))
+                                       self.context, permissions_for_context(self.context),
+                                       execution_scope=settings.operational_task_execution_scope)
         for event in changes:
             # Period diagnosis owns measurement notifications during manual steps.
             # Retain rule events as evidence; quality alerts remain independent.
@@ -503,6 +505,7 @@ class ScadaReplayService:
                 tasks = OperationalTaskService(
                     OperationalTaskRepository(self.repo.connection, self.context.project_id),
                     self.context, permissions_for_context(self.context),
+                    execution_scope=settings.operational_task_execution_scope,
                 )
                 await tasks.advance_replay_investigation(UUID(incident["task_id"]), {
                     "replay_id": document["replay_id"], "knowledge_cutoff": monitoring["knowledge_cutoff"],
@@ -520,6 +523,7 @@ class ScadaReplayService:
             OperationalTaskRepository(self.repo.connection, self.context.project_id),
             self.context,
             permissions_for_context(self.context),
+            execution_scope=settings.operational_task_execution_scope,
         )
         external = incident["external_id"]
         pressure = monitoring["pressure"]