feat(mesh-phase4): DriverHostActor runs ConfigDb-free (LocalDb alarm store, guarded acks)

Nullable ConfigDb factory; UpsertNodeDeploymentState no-ops when absent
(central persists acks from the ApplyAck); scripted-alarm condition state
served from the LocalDb store instead of the ConfigDb-backed Ef store.
Combines Phase-4 Tasks 4 + 6. Removes the interim dbFactory! cast.

Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW

docs/plans/2026-07-23-mesh-phase4-cut-driver-configdb.md.tasks.json

@@ -54,7 +54,9 @@
     {
       "id": 5,
       "subject": "Task 5: alarm_condition_state LocalDb table + LocalDbAlarmConditionStateStore",
-      "status": "pending"
+      "status": "completed",
+      "commit": "4f4cdd05",
+      "result": "16 new tests; SPEC-COMPLIANT + APPROVED (ON CONFLICT DO UPDATE replication-safe). Fold Kind+null-audit test polish into Task 4/6"
     },
     {
       "id": 6,