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/Dockerfile

@@ -0,0 +1,14 @@
+FROM node:18-alpine
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install --production
+
+COPY server.js ./server.js
+COPY data/apps.json ./data/apps.json
+
+ENV PORT=3000
+EXPOSE 3000
+
+CMD ["node", "server.js"]