test(deployment): add revisionHistoryLimit tests and deployment notes

Add helm-unittest tests for revisionHistoryLimit:
- Default value (3) verification
- Custom values support (0, 1, 5, 100)
- Ability to disable revision history

Add NOTES.txt with revisionHistoryLimit information:
- Show configured revision history limit
- Warning when disabled (0)
- Note for minimal history (1)
- Rollback command example for normal values

This parameter controls how many old ReplicaSets are retained
for rollback purposes, reducing etcd storage usage.

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

charts/jellyfin/templates/NOTES.txt

@@ -0,0 +1,35 @@
+Thank you for installing {{ .Chart.Name }}.
+
+Your release is named {{ .Release.Name }}.
+
+To learn more about the release, try:
+
+  $ helm status {{ .Release.Name }}
+  $ helm get all {{ .Release.Name }}
+
+{{- if .Values.ingress.enabled }}
+
+Jellyfin is available via Ingress at:
+{{- range .Values.ingress.hosts }}
+  http{{ if $.Values.ingress.tls }}s{{ end }}://{{ .host }}{{ (index .paths 0).path }}
+{{- end }}
+{{- else }}
+
+To access Jellyfin, you can use port-forwarding:
+
+  $ kubectl port-forward --namespace {{ .Release.Namespace }} svc/{{ include "jellyfin.fullname" . }} {{ .Values.service.port }}:{{ .Values.service.port }}
+
+Then visit http://localhost:{{ .Values.service.port }} in your browser.
+{{- end }}
+
+Deployment Configuration:
+  Revision History Limit: {{ .Values.revisionHistoryLimit }}
+  {{- $limit := int .Values.revisionHistoryLimit }}
+  {{- if eq $limit 0 }}
+  ⚠ WARNING: Revision history is disabled - rollback will not be possible!
+  {{- else if eq $limit 1 }}
+  ⚠ NOTE: Only 1 revision kept - limited rollback capability
+  {{- else }}
+  You can rollback to any of the last {{ .Values.revisionHistoryLimit }} revisions using:
+    kubectl rollout undo deployment/{{ include "jellyfin.fullname" . }} --namespace {{ .Release.Namespace }}
+  {{- end }}