0.11.0

Changed

• The library index moved from one monolithic library.json file to a real
  SQLite database (library.db), migrated automatically on first launch of
  this version — your old library.json is kept as library.json.bak, never
  deleted. Rescans and detail fills now write only the rows that actually
  changed instead of rewriting the whole file every time; on a 5,800+ book
  library this cut a routine background write from a full-file rewrite down
  to single-digit milliseconds. No visible change to search, sort, or
  filtering — this is purely a storage change underneath.