feat(docker): add Docker Compose deployment for Dokploy

- backend/Dockerfile: Python 3.12-slim, uvicorn on port 8000
- frontend/Dockerfile: multi-stage Node build + nginx:alpine serve
- frontend/nginx.conf: proxy /api to backend, SPA routing for Vue Router
- docker-compose.yml: backend+frontend services with Traefik labels
- fix(cors): use settings.frontend_url instead of hardcoded localhost

Fixes Nixpacks detection failure (requirements.txt/package.json not at root).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,42 @@
+version: "3.8"
+
+services:
+  backend:
+    build: ./backend
+    restart: unless-stopped
+    environment:
+      - SECRET_KEY=${SECRET_KEY:-change-me-in-production}
+      - DATABASE_URL=sqlite:////data/space_booking.db
+      - FRONTEND_URL=${FRONTEND_URL:-http://localhost}
+      - SMTP_HOST=${SMTP_HOST:-localhost}
+      - SMTP_PORT=${SMTP_PORT:-1025}
+      - SMTP_ENABLED=${SMTP_ENABLED:-false}
+    volumes:
+      - backend_data:/data
+      - uploads_data:/app/uploads
+    networks:
+      - internal
+
+  frontend:
+    build: ./frontend
+    restart: unless-stopped
+    networks:
+      - internal
+      - dokploy-network
+    depends_on:
+      - backend
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.space-booking.rule=Host(`${DOMAIN:-space-booking.roa.romfast.ro}`)"
+      - "traefik.http.routers.space-booking.tls=true"
+      - "traefik.http.services.space-booking.loadbalancer.server.port=80"
+
+volumes:
+  backend_data:
+  uploads_data:
+
+networks:
+  internal:
+    driver: bridge
+  dokploy-network:
+    external: true