Add admin panel API with CRUD for apps

- Express.js backend with JWT authentication
- CRUD endpoints for apps management
- Health check endpoint
- Dockerfile per admin API (Node 18 Alpine)
- Kubernetes: admin-api deployment, service, ingress
- Admin panel at http://admin.apps.local
- Updated nginx.conf to route /api to admin API
- Fixed ingress rules for separate web and admin services

backend/k8s/admin-service.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: admin-api
+  labels:
+    app: admin-api
+spec:
+  type: ClusterIP
+  ports:
+  - port: 80
+    targetPort: 3000
+    protocol: TCP
+    name: http
+  selector:
+    app: admin-api