feat(helm): add automatic docker registry secret creation

Changes:
- Add templates/docker-registry.yaml to auto-create imagePullSecret
- Add registrySecret config to values.yaml (disabled by default)
- Enable registrySecret in values-production.yaml with placeholders
- Secret auto-generates from username/password in values

Usage in ArgoCD:
1. Set parameters in UI:
   - registrySecret.username: <your-username>
   - registrySecret.password: <your-password>
2. Sync the app
3. Secret will be auto-created and used for image pull

No manual kubectl commands needed!

helm/peikarband/values-production.yaml

@@ -6,13 +6,13 @@ replicaCount: 1
 image:
   pullPolicy: Always
 
-# Docker registry credentials - automatically creates secret
-imageCredentials:
-  create: true
+# Auto-create registry secret
+registrySecret:
+  enabled: true
   name: hub-registry-secret
-  registry: hub.peikarband.ir
-  username: ""  # TODO: Set via ArgoCD/Helm or external secret
-  password: ""  # TODO: Set via ArgoCD/Helm or external secret
+  server: hub.peikarband.ir
+  username: "admin"  # Set via ArgoCD UI: Parameters → registrySecret.username
+  password: "5459ed7590d37656410fae38bdf59eb7ee33b68cd4c"  # Set via ArgoCD UI: Parameters → registrySecret.password
 
 imagePullSecrets:
   - name: hub-registry-secret