test(persistence): add comprehensive cache volume tests
Add helm-unittest tests for dedicated cache volume persistence:
- Default emptyDir behavior
- PVC creation when enabled
- hostPath configuration
- Volume mount verification
- PVC size, access mode, storage class configuration
- Annotations support
- Existing claim usage
- Type-specific behavior (pvc vs hostPath vs emptyDir)
Add NOTES.txt with persistence information:
- Show config, media, and cache volume types
- Display cache volume details when enabled
- Benefits explanation for cache volume
- Warning for hostPath usage
Tests ensure cache persistence works correctly for all scenarios.
Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Aleksei Sviridkin <f@lex.la>
