feat: add bounded business state observability

deploy/monitoring/orbit.rules.yml

@@ -25,6 +25,22 @@ groups:
         annotations:
           summary: "Orbit background batches are failing"
           description: "Use process logs and durable task/workflow audit to investigate. Batch errors are not business failures."
+      - alert: OrbitBusinessSnapshotStalled
+        expr: (time() - orbit_business_snapshot_last_success_timestamp_seconds{job="orbit"} > 30) and on (job, instance) (time() - orbit_process_start_time_seconds{job="orbit"} > 60)
+        for: 1m
+        labels:
+          severity: warning
+        annotations:
+          summary: "Orbit has no recent successful business-state snapshot"
+          description: "Inspect the bounded sampler timeout/error counter and MySQL health; the last state gauges may be stale."
+      - alert: OrbitBusinessSnapshotTruncated
+        expr: orbit_business_snapshot_truncated{job="orbit"} == 1
+        for: 5m
+        labels:
+          severity: warning
+        annotations:
+          summary: "Orbit business-state snapshot reached its sample cap"
+          description: "State gauges are bounded samples, not exact global counts; use authoritative database queries and capacity review."
       - alert: OrbitDBPoolWaiting
         expr: rate(orbit_db_wait_duration_seconds_total{job="orbit"}[5m]) > 0.1
         for: 5m