Quitting mid-transfer now asks (Keep Syncing / Quit Anyway) from
closeEvent, which every quit path hits — including the self-update
restart, which previously bypassed closeEvent via a bare quit() and now
routes through close(). A running sync holds its own GNOME inhibitor
(suspend + logout, "Syncing a playlist to a device") so the machine
won't sleep or shutdown/restart under a copy.
Along the way: the Inhibit D-Bus call marshaled Python ints as signed
against GNOME's (susu) signature, so every call was rejected and the
playback sleep inhibitor had silently never worked — _uint fixes both
holders (verified live: cookies taken, IsInhibited flips, releases
clean).
Also investigated trav's mid-copy Syncthing question: the transfer works
from a click-time snapshot and never reads live library state, so remote
changes can't corrupt it — no state freeze needed. Hardened the one real
gap: a source file relocated under the queue (remote metadata edit
moving files) is now skipped, dropped from the m3u, and reported,
instead of aborting the whole sync.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>