Add Linux App Store Web Portal with Kubernetes deployment

- React-style static web portal with Tailwind CSS
- OS detection (Debian/Ubuntu, Fedora, Arch, Generic)
- Dynamic install commands (apt://, appstream://, flatpak)
- 9 pre-configured applications
- Kubernetes: 2 replicas, LoadBalancer service, Nginx ingress
- GitLab Container Registry (git.giaco.net/capitano/webapplinux)
- Namespace: linuxwebapp
- Added Dockerfile, nginx.conf, deploy.sh, docker-compose.yml
- Updated README.md with deployment instructions

docker-compose.yml

@@ -0,0 +1,11 @@
+services:
+  web:
+    build: .
+    ports:
+      - "8080:80"
+    volumes:
+      - ./frontend:/usr/share/nginx/html
+      - ./nginx.conf:/etc/nginx/conf.d/default.conf:ro
+    environment:
+      - NGINX_HOST=apps.local
+      - NGINX_PORT=80