Fix Docker build - Add PORT environment variable

- Add PORT=3000 to both Dockerfile and docker-compose.yml
- Ensure proper file ownership in standalone build
- Fix potential 404 routing issues

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

docker-compose.yml

@@ -9,6 +9,7 @@ services:
       - "6969:3000"
     environment:
       - NODE_ENV=production
+      - PORT=3000
     networks:
       - dokploy-network
     labels: