The prod image baked the app user at uid 1002, but install.sh chowns the
bind-mounted ./run to the clusev host user. On a host where clusev != 1002 the
app process could not write the restart/update sentinel — the dashboard button
showed 'läuft' while nothing happened on the server. Pass APP_UID/APP_GID =
HOST_UID/HOST_GID into the prod build so the in-image app user matches clusev
and ./run is writable. Also surface a failed sentinel write as an error toast
instead of a stuck 'running' state (requestUpdate now returns bool).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>