Migration recovery backups no longer re-copy Folio-Backups (up to 21x bloat). bookChangedSince tracks visited dev:ino so a symlink loop in the book cannot wedge the main-process interval tick. Snapshot toggle check aligned to === false; drop dead home-shortening branch in Settings.
Background autosave toggle plus whole-book snapshots (default <book>/Folio-Backups, configurable location, retention, interval) with a one-minute change check in the main process. New Settings modal (sidebar, Ctrl+, , File menu) exposes autosave, snapshots, folder picker, and Snapshot now.