fix(platform): apply production hardening from audit plan

Close billing, tenancy, migration, build, and CI/CD gaps identified in the
audit: wallet/gateway guards, full-UUID namespaces, idempotent migrations with
base schema, stateful service stability, safer Dockerfiles/git builds, and
platform chart hardening (Redis auth, RollingUpdate, backups, Swagger off).

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/helm/cloudhost-platform/templates/postgres-deployment.yaml

@@ -19,6 +19,10 @@ spec:
       labels:
         app: {{ include "cloudhost-platform.postgres.fullname" . }}
     spec:
+      {{- with .Values.postgres.imagePullSecrets }}
+      imagePullSecrets:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
       containers:
         - name: postgres
           image: {{ .Values.images.postgres | quote }}