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/frontend-deployment.yaml

@@ -19,7 +19,7 @@ spec:
     spec:
       containers:
         - name: frontend
-          image: graphrag-frontend:latest
+          image: registry.plfai.cn/graphrag-frontend:latest
           imagePullPolicy: IfNotPresent
           ports:
             - containerPort: 80