feat(persistence): add cache volume persistence support

Add dedicated cache volume configuration to reduce wear on SD cards and improve
performance by allowing cache to be stored on separate storage.

Changes:
- Add persistence.cache configuration in values.yaml with support for:
  - PVC (default type when enabled)
  - hostPath for direct host mount
  - emptyDir (default when disabled)
- Add cache volume mount at /cache in deployment
- Add cache PersistentVolumeClaim template
- Support for existing PVC via existingClaim
- Configurable size (default 10Gi), accessMode, storageClass, and annotations
- Update Chart version from 2.5.0 to 2.5.1
- Add Artifact Hub changelog annotation

The cache volume is disabled by default to maintain backward compatibility.
Users can enable it via:

```yaml
persistence:
  cache:
    enabled: true
    type: pvc
    size: 10Gi
```

This addresses the use case mentioned in #62 where users want to avoid SD card
wear by storing cache on separate persistent storage.

Fixes: #62

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Aleksei Sviridkin <f@lex.la>

charts/jellyfin/README.md

@@ -1,6 +1,6 @@
 # jellyfin
 
-![Version: 2.5.0](https://img.shields.io/badge/Version-2.5.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 10.11.2](https://img.shields.io/badge/AppVersion-10.11.2-informational?style=flat-square)
+![Version: 2.5.1](https://img.shields.io/badge/Version-2.5.1-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 10.11.2](https://img.shields.io/badge/AppVersion-10.11.2-informational?style=flat-square)
 
 A Helm chart for Jellyfin Media Server
 
@@ -87,6 +87,13 @@ helm install my-jellyfin jellyfin/jellyfin -f values.yaml
 | metrics.serviceMonitor.tlsConfig | object | `{}` | TLS configuration for scraping metrics |
 | nameOverride | string | `""` | Override the default name of the chart. |
 | nodeSelector | object | `{}` | Node selector for pod scheduling. |
+| persistence.cache.accessMode | string | `"ReadWriteOnce"` | PVC specific settings, only used if type is 'pvc'. |
+| persistence.cache.annotations | object | `{}` | Custom annotations to be added to the PVC |
+| persistence.cache.enabled | bool | `false` | set to false to use emptyDir |
+| persistence.cache.hostPath | string | `""` | Path on the host node for cache storage, only used if type is 'hostPath'. |
+| persistence.cache.size | string | `"10Gi"` |  |
+| persistence.cache.storageClass | string | `""` | If undefined (the default) or set to null, no storageClassName spec is set, choosing the default provisioner. |
+| persistence.cache.type | string | `"pvc"` | Type of volume for cache storage (pvc, hostPath, emptyDir). If 'enabled' is false, 'emptyDir' is used regardless of this setting. |
 | persistence.config.accessMode | string | `"ReadWriteOnce"` |  |
 | persistence.config.annotations | object | `{}` | Custom annotations to be added to the PVC |
 | persistence.config.enabled | bool | `true` | set to false to use emptyDir |