fix: cleanup k8s configs, add deploy.sh, remove hardcoded secrets

- Add one-click deploy script (k8s/deploy.sh) for test + prod
- Add startupProbe to backend (60x10s = 10min grace for ML model loading)
- Add configmap.yaml and secret.yaml (envsubst from backend/.env)
- Fix image URLs: add registry.plfai.cn prefix
- Fix frontend: API base URL relative (/api/v1), login-required mode
- Remove hardcoded localhost references from frontend
- Clean broken kustomize overlays
- Add nodeAffinity for backend→k8smaster, frontend→plf-cvm/k8smaster
- Remove dead ReplicaSets and stale pods during deploy

k8s/base/secret.yaml

@@ -0,0 +1,9 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: graphrag-secrets
+type: Opaque
+stringData:
+  DEEPSEEK_API_KEY: "${DEEPSEEK_API_KEY}"
+  MINERU_API_TOKEN: "${MINERU_API_TOKEN}"
+  KEYCLOAK_CLIENT_SECRET: "${KEYCLOAK_CLIENT_SECRET}"