fix(build): default Kaniko and init images to Harbor via Helm values

User-app builds no longer pull gcr.io/docker.io directly when build.images
is configured in values.yaml, fixing ImagePullBackOff on clusters without
upstream registry access.

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

backend/helm/cloudhost-platform/values.yaml

@@ -28,6 +28,16 @@ images:
     tag: "1.0.0"
     pullPolicy: IfNotPresent
 
+# Kaniko job images — defaults pull from Harbor proxy-cache.
+# Override any line for a different registry/tag.
+build:
+  images:
+    kaniko: registry.abrban.com/proxy-gcr/kaniko-project/executor:v1.23.2
+    alpine: registry.abrban.com/proxy-dockerhub/library/alpine:3.19
+    alpineGit: registry.abrban.com/proxy-dockerhub/alpine/git:2.43.0
+  # Prefix for Docker Hub images in generated user-app Dockerfiles (node, php, …)
+  baseImageRegistry: registry.abrban.com/proxy-dockerhub/library
+
 postgres:
   enabled: true
   database: cloudhost