fix(helm): disable backend PVC when using PostgreSQL

The backend PVC was originally used for SQLite storage but is no longer
needed when PostgreSQL is enabled. This change automatically disables
the PVC creation when postgres.enabled=true, saving 1Gi of storage.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: Clément VALENTIN

helm/myelectricaldata/templates/backend/backend-deployment.yaml

@@ -211,7 +211,8 @@ spec:
               mountPath: /logs
       volumes:
         - name: data
-          {{- if .Values.backend.persistence.enabled }}
+          {{- /* Use PVC only for SQLite mode (postgres.enabled is false) */ -}}
+          {{- if and .Values.backend.persistence.enabled (not .Values.postgres.enabled) }}
           persistentVolumeClaim:
             claimName: {{ include "myelectricaldata.backend.fullname" . }}
           {{- else }}

helm/myelectricaldata/templates/backend/backend-pvc.yaml

@@ -1,4 +1,5 @@
-{{- if and .Values.backend.enabled .Values.backend.persistence.enabled -}}
+{{- /* Backend PVC is only needed for SQLite mode (when postgres.enabled is false) */ -}}
+{{- if and .Values.backend.enabled .Values.backend.persistence.enabled (not .Values.postgres.enabled) -}}
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:

helm/myelectricaldata/values.yaml

@@ -53,7 +53,8 @@ backend:
     timeoutSeconds: 3
     failureThreshold: 3
 
-  # Persistent storage for data
+  # Persistent storage for SQLite database (only used when postgres.enabled is false)
+  # When using PostgreSQL, this PVC is automatically disabled
   persistence:
     enabled: true
     size: 1Gi