Docker socket unreachable
failed to connect to the docker API at unix:///var/run/docker.sock; check if the path is correct and if the daemon is running: dial unix /var/run/docker.sock: connect: no such file or directory
Set DOCKER_GID to the docker socket's group and recreate the app container: Linux `stat -c %g /var/run/docker.sock` (often 999); macOS (OrbStack / Docker Desktop) `0`.
Data directories not writable
not writable: osm, gtfs, otp (under /work/data)
Check the compose volume mounts for ./data/* — region applies need them.