feat: estrutura inicial do gerenciador de subdomínios

- backend Express com endpoints Hostinger DNS API
- frontend React+Vite+Tailwind com card de API key
- docker-compose (frontend:3014, backend:8019, nginx:8021)
- Traefik label para subdominio.clube67.com

docker-compose.yml

@@ -0,0 +1,42 @@
+services:
+  frontend:
+    build:
+      context: ./frontend
+    container_name: subdominio-frontend
+    restart: unless-stopped
+    networks:
+      - subdominio-net
+
+  backend:
+    build:
+      context: ./backend
+    container_name: subdominio-backend
+    restart: unless-stopped
+    volumes:
+      - ./backend/config.json:/app/config.json
+    networks:
+      - subdominio-net
+
+  nginx:
+    image: nginx:alpine
+    container_name: subdominio-nginx
+    restart: unless-stopped
+    ports:
+      - "8021:8021"
+    volumes:
+      - ./nginx/default.conf:/etc/nginx/conf.d/default.conf:ro
+    depends_on:
+      - frontend
+      - backend
+    networks:
+      - subdominio-net
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.subdominio.rule=Host(`subdominio.clube67.com`)"
+      - "traefik.http.routers.subdominio.entrypoints=websecure"
+      - "traefik.http.routers.subdominio.tls.certresolver=le"
+      - "traefik.http.services.subdominio.loadbalancer.server.port=8021"
+
+networks:
+  subdominio-net:
+    driver: bridge