fix: Use built-in node user to avoid GID conflicts

- Remove custom nodejs user creation that was causing GID 1000 conflicts
- Use the built-in 'node' user from node:alpine image
- Update volume mount path from /home/nodejs to /home/node
- Simplify Dockerfile by removing unnecessary user creation

This fixes the "addgroup: gid '1000' in use" error during Docker build.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

docker-compose.dev.yml

@@ -27,7 +27,7 @@ services:
       - backend-logs:/app/logs
       - backend-temp:/app/temp
       - backend-node-modules:/app/node_modules
-      - ~/.mc:/home/nodejs/.mc:ro
+      - ~/.mc:/home/node/.mc:ro
     depends_on:
       - redis
     networks: