fix: disable migrate job and cleanup cronjob for arm64 cluster

- Disable migrate job (uses app images that need arm64 builds)
- Disable cleanupStaging cronjob (minio/mc image pull failing)
- Worker remains enabled with dev-arm64 tag

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

helm/porthole/values-cluster.yaml

@@ -11,10 +11,14 @@ secrets:
     accessKeyId: "FwGiBwCXKuQdthR1QLa"
     secretAccessKey: "OtmAz9m7o941wG1Gms2yItyqxd6gCWY8k4LJVBX"
 
-# Enable jobs and apps now that images are built
+# Temporarily disable jobs until arm64 images are available
 jobs:
   migrate:
-    enabled: true
+    enabled: false
+
+cronjobs:
+  cleanupStaging:
+    enabled: false  # minio/mc image pull failing on arm64
 
 web:
   enabled: false  # Temporarily disabled - web arm64 build times out