The "Add game…" button only prompted for a name (single-field QInputDialog),
so a custom game couldn't be given its launch command or log dir from the GUI —
the command/logdir were CLI-only, leaving SPT unlaunchable from the app. Replace
it with a proper dialog: name + an optional launch command/script (with a file
browser) + an optional log folder (auto-detected from the script's folder when
left blank), wired to the existing customgames.add(command=, logdir=).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>