Remove user/permission management for Dokploy deployment

- Dockerfile: remove appuser creation, run everything as root
- www.conf: switch php-fpm workers to www-data
- entrypoint.sh: remove all chown and git safe.directory workarounds
- docker-compose.yml: remove USER_ID/GROUP_ID build args
- .env.example: remove USER_ID/GROUP_ID variables

docker/php/www.conf

@@ -1,9 +1,9 @@
 [www]
-user = appuser
-group = appuser
+user = www-data
+group = www-data
 listen = 0.0.0.0:9000
-listen.owner = appuser
-listen.group = appuser
+listen.owner = www-data
+listen.group = www-data
 
 pm = dynamic
 pm.max_children = 20