feat(helm): add cloudhost-app Helm chart for all runtimes

- deployment.yaml with imagePullSecrets, health probes, WordPress volumes
- db-deployment.yaml for PostgreSQL/MySQL with readiness/liveness probes
- ingress.yaml with cert-manager TLS
- registry-pull-secret.yaml for insecure registries
- PVCs and secrets with helm.sh/resource-policy: keep
- _helpers.tpl with shared template functions
- values.yaml with comprehensive defaults

backend/helm/cloudhost-app/values.yaml

@@ -0,0 +1,59 @@
+# ────────────────────────────────────────────────────────────
+# CloudHost Application — default Helm values
+# These are overridden per-app at install/upgrade time.
+# ────────────────────────────────────────────────────────────
+
+# ── Application ──────────────────────────────────────────
+app:
+  name: my-app
+  namespace: user-default
+  runtime: nodejs          # nodejs | laravel | wordpress
+  image: ""                # e.g. registry.example.com/my-app:v1
+  port: 3000
+  replicas: 1
+
+# ── Resources ────────────────────────────────────────────
+resources:
+  cpuRequest: "100m"
+  cpuLimit: "500m"
+  memoryRequest: "128Mi"
+  memoryLimit: "512Mi"
+
+# ── Environment variables (injected via Secret) ─────────
+envVars: {}
+  # KEY: value
+
+# ── Ingress ──────────────────────────────────────────────
+ingress:
+  enabled: true
+  subdomain: ""            # <subdomain>.<domain>
+  domain: "apps.cloudhost.ir"
+  clusterIssuer: letsencrypt-prod
+
+# ── Database (MySQL or PostgreSQL) ───────────────────────
+database:
+  enabled: false
+  type: postgresql         # mysql | postgresql
+  version: "16"            # postgres version or mysql version
+  image: ""                # auto-computed if empty
+  port: 5432               # 5432 for pg, 3306 for mysql
+  username: appuser
+  password: ""
+  storageSize: "1Gi"
+  resources:
+    cpuRequest: "100m"
+    cpuLimit: "500m"
+    memoryRequest: "256Mi"
+    memoryLimit: "512Mi"
+
+# ── WordPress-specific ───────────────────────────────────
+wordpress:
+  enabled: false
+  wpContentStorageSize: "2Gi"
+
+# ── Change metadata ─────────────────────────────────────
+changeCause: ""
+
+# ── Registry (for imagePullSecret) ──────────────────────
+registry:
+  url: "localhost:30500"