feat: full GKE/prod deployment pipeline from UI to Artifact Registry

## GCP / Cluster Environment Screen
- Auto-populate Cloud tab from conf/prod/gcp.cfg on screen open (org_id,
  billing_account, billing_project, project_id)
- gcloud auth validity checked on screen startup; friendly modal dialog
  streams gcloud auth login output live so user never leaves the app
- Live GKE cluster browser: fetches clusters via gcloud container clusters
  list, displays with checkmark selector, auto-selects saved cluster
- Selecting a cluster runs get-credentials, sets KUBECONFIG/KUBECONTEXT,
  and syncs the region dropdown to the selected cluster's location
- Region dropdown populated live from gcloud compute regions list with
  checkmark on currently selected region; graceful fallback when offline
- New 'GCP Storage' tab with workload->StorageClass mapping (CNPG->premium-rwo,
  Redis/Monitoring->standard-rwo, Garage->garage-hdd) and Fetch from Cluster
- Provider readonly field styled correctly (no solid-black on macOS)
- Stale knoe.cfg/conf/knoe.cfg symlinks removed; all config I/O now
  resolves env-specific paths via knoe_conf.entrypoint_path()

## GKE Autopilot Compatibility (Common Services)
- Synology iSCSI StorageClass and static PVs guarded behind KNOE_MODE!=k8s
  in init_openbao.sh (GKE Autopilot forbids hostPath/iSCSI volumes)
- In-cluster Docker registry (hostPath) skipped in k8s mode; GCP Artifact
  Registry used instead
- Kong renamed knoe-svc-kong in k8s mode; all health-check kubectl calls in
  init_common_services.sh and status_common_services.sh updated accordingly
- DNS endpoints switched from *.knoe.org to *.knoe.dev in k8s mode
  (api.knoe.dev, git.knoe.dev, svc.knoe.dev); ingress uses gce class
- New GKE-clean Kong manifests under deploy/opentofu/k8s/manifests/knoe/:
  no k3s node affinity, explicit Autopilot resource requests/limits

## Garage S3 Store (GKE)
- New garage-statefulset-gcp.yaml targeting garage-hdd StorageClass
  (pd-standard, avoids SSD_TOTAL_GB quota exhaustion in us-west3)
- New storageclass-gcp-hdd.yaml (pd-standard, Retain, WaitForFirstConsumer)
- GCP StorageClass manifests skipped on re-runs (Autopilot built-ins are
  immutable; skip-if-exists guard added)
- PVC deletion guard extended to cover any storageClass (not just synology)
  so stale claims are cleaned before StatefulSet recreation

## Topology (GKE Autopilot)
- DaemonSet collector skipped in prod mode (forbidden in kube-system by
  GKE Warden); Kubernetes-only node facts path used instead
- All ready GKE nodes assumed cnpg-eligible and monitoring-eligible without
  taint/synology-mount checks (skip_collector + assume_nodes_eligible flags)

## KUBECONFIG / kubectl (k8s mode)
- actions.py: new elif mode==k8s branch sets KUBECONFIG=~/.kube/config
  and injects KUBECONTEXT from knoe_cfg_data into script env
- _build_kubectl_cmd falls back to Global.KUBECONTEXT when
  init_cluster.selected_kubectx is empty
- _activate_selected_gke_cluster persists KUBECONFIG/KUBECONTEXT to
  knoe_cfg_data and saves knoe.cfg immediately after get-credentials

## Database Build Screen (GKE)
- Registry display shows correct Artifact Registry URL
  (<region>-docker.pkg.dev/<project>/<namespace>/knoe-db) in green
- Build+push: gcloud auth configure-docker, auto-creates AR repository
  named after SERVICE_NAMESPACE (e.g. knoe-system) if missing, then
  docker tag + push; falls back to gcr.io if region unavailable
- GCP config loaded from conf/prod/gcp.cfg on every screen entry;
  keys normalised to lowercase so project_id lookup is always consistent

## Config / Namespace persistence
- knoe_conf.py activate_environment: symlink creation removed; sets
  CLUSTER_ENV env-var so all subsequent calls resolve correct env directory
- knoe/ui/screens/__init__.py: startup config load uses entrypoint_path()
  instead of hardcoded conf/knoe.cfg; seeds SERVICE_NAMESPACE=knoe-system
  for managed envs so Common Services never defaults to 'default'
- cfg.py _save_knoe_cfg: saves to env-specific path via entrypoint_path()
- etc/knoe_cfg.sh: removed all ln -snf symlink creation

Co-authored-by: Junie <junie@jetbrains.com>
