fix: [alert] VeleroBackupStale (velero) (#780)

Updates managed by image-automation-controller.

kubernetes/apps/monitoring-rules/prometheusrule-velero.yaml

@@ -58,10 +58,30 @@ spec:
           # VeleroBackupFailed alert fires on the first failure regardless — so
           # nothing is hidden, only the escalation to critical is deferred
           # until a second cycle confirms it.
+          #
+          # The `and on(schedule) velero_backup_last_status` gate exists because
+          # velero_backup_last_successful_timestamp is an in-process gauge that
+          # velero does NOT retract when a Schedule is deleted: the series just
+          # stops being updated, ages past 60h and pages critical forever, for a
+          # schedule that no longer exists. That is what decommissioning
+          # netbird-backup-daily did on 2026-09-01.
+          #
+          # velero_backup_last_status is the same shape but IS retracted on
+          # Schedule deletion, so it works as a liveness set for "this schedule
+          # still exists". It hides nothing: velero repopulates it for every
+          # existing Schedule on its first scrape after a restart (verified
+          # across the three pods of the 2026-08-27 rollout), and it is written
+          # on failed runs too (0) as well as successful ones (1) — so a
+          # schedule that exists and is failing, or that exists and has stopped
+          # firing, still carries the series and still alerts.
           expr: |
-            time() - velero_backup_last_successful_timestamp{schedule!=""} > 60 * 3600
-            and
-            velero_backup_last_successful_timestamp{schedule!=""} > 0
+            (
+              time() - velero_backup_last_successful_timestamp{schedule!=""} > 60 * 3600
+              and
+              velero_backup_last_successful_timestamp{schedule!=""} > 0
+            )
+            and on(schedule)
+            velero_backup_last_status
           for: 10m
           labels:
             severity: critical

kubernetes/infrastructure/cnpg-barman-plugin/manifest.yaml

@@ -937,7 +937,7 @@ subjects:
 # with no marker. Re-apply this block, or the skew silently returns.
 apiVersion: v1
 stringData:
-  SIDECAR_IMAGE: ghcr.io/cloudnative-pg/plugin-barman-cloud-sidecar:v0.14.0 # {"$imagepolicy": "flux-system:cnpg-barman-plugin-sidecar"}
+  SIDECAR_IMAGE: ghcr.io/cloudnative-pg/plugin-barman-cloud-sidecar:v0.15.0 # {"$imagepolicy": "flux-system:cnpg-barman-plugin-sidecar"}
 kind: Secret
 metadata:
   name: plugin-barman-cloud-kg5c2795f7
@@ -998,7 +998,7 @@ spec:
             secretKeyRef:
               key: SIDECAR_IMAGE
               name: plugin-barman-cloud-kg5c2795f7
-        image: ghcr.io/cloudnative-pg/plugin-barman-cloud:v0.14.0 # {"$imagepolicy": "flux-system:cnpg-barman-plugin"}
+        image: ghcr.io/cloudnative-pg/plugin-barman-cloud:v0.15.0 # {"$imagepolicy": "flux-system:cnpg-barman-plugin"}
         name: barman-cloud
         ports:
         - containerPort: 9090