Define scoped Forgejo native backup on the Scaleway primary

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a06ecb-456a-71c2-b41e-0755d336e883

helm/forgejo-db-cluster.yaml

@@ -4,7 +4,7 @@
 #
 # Apply: KUBECONFIG=~/.kube/config-hosteurope make forgejo-db-deploy
 # Status: make forgejo-db-status
-# Backup: make forgejo-backup (pg_dump + forgejo dump → Nextcloud; docs/forgejo-backup.md)
+# Primary: Scaleway Barman + WAL. Secondary: make forgejo-backup (Nextcloud + age).
 #
 # Pre-condition: forgejo-db-credentials Secret in databases namespace.
 # See helm/forgejo-db-secret.sops.yaml.template
@@ -49,4 +49,22 @@ spec:
       database: forgejo
       owner: forgejo
       secret:
-        name: forgejo-db-credentials
+        name: forgejo-db-credentials
+  backup:
+    retentionPolicy: 30d
+    barmanObjectStore:
+      destinationPath: s3://railiance-platform-pg-backup/platform-pg/forgejo-db/
+      endpointURL: https://s3.nl-ams.scw.cloud
+      s3Credentials:
+        accessKeyId:
+          name: platform-pg-backup-s3
+          key: ACCESS_KEY_ID
+        secretAccessKey:
+          name: platform-pg-backup-s3
+          key: ACCESS_SECRET_KEY
+      wal:
+        compression: gzip
+        maxParallel: 2
+      data:
+        compression: gzip
+        jobs: 2