Rework jellyfin-ha into a true-HA StatefulSet deployment

Turn the single-replica jellyfin-ha app into a proper high-availability
deployment so the fork's Redis-coordinated distributed transcoding and
PostgreSQL main database can actually be exercised.

- Replace the Deployment with a 2-replica StatefulSet for stable pod
  identity; set JELLYFIN_INSTANCE_ID from metadata.name (the fork's Redis
  transcode-lease owner id), add soft podAntiAffinity and a PDB
  minAvailable 1.
- Move the main Jellyfin DB to PostgreSQL via a CloudNativePG trio
  (3-instance Cluster, PgBouncer Pooler, Ceph RGW barman backups) mirroring
  the litellm pattern; an init container writes database.xml selecting the
  fork's Jellyfin-PostgreSQL provider and the DSN is composed from the
  CNPG-generated app secret pointed at the pooler.
- Share /config on an RWX cephfs PVC across replicas; keep /cache per-pod
  via a volumeClaimTemplate.
- Fix the transcode mount to the fork's real path /config/transcodes on the
  RWX PVC (raid5) so a surviving pod can resume the segments of the pod it
  takes over.
- Add Intel iGPU hardware transcoding via the gpu.intel.com/i915 device
  plugin resource plus render/video supplemental groups.
- Switch the Service to sessionAffinity ClientIP to reduce transcode churn.
- Disable UDP auto-discovery. Library scans still run on every replica; a
  single-scanner leader election is a planned follow-up.

apps/base/jellyfin/pvc-transcode.yaml

@@ -1,7 +1,8 @@
 ---
 # Shared transcode scratch. ReadWriteMany is the hard requirement for the HA
 # fork: a taking-over pod must read the in-flight HLS segments written by the
-# pod it replaces. Scratch data, so delete reclaim policy.
+# pod it replaces. Scratch data (delete reclaim); raid5 avoids the raid6
+# double-parity write penalty on the many small HLS segment writes.
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:
@@ -13,5 +14,5 @@ spec:
   resources:
     requests:
       storage: 100Gi
-  storageClassName: cephfs-raid6-delete
+  storageClassName: cephfs-raid5-delete
   volumeMode: Filesystem