Follow-up to the 2026-10-18 review of the v1→v2 migration. Start-up
(finishing a pending restore, then migrating or reconciling) now runs under
the lock every save takes, so a second tab's save cannot be overwritten;
where no lock exists it opens unlocked, as before. The automatic backups get
a size cap like Back up now's: past it the oldest are dropped, never the
newest, leaving the main save room to grow.
Co-Authored-By: Claude Opus 5.5 <[email protected]>