v3.0.0

Changed

• New UI framework generation. BookDB now runs on Avalonia 12, the latest major version of its cross-platform UI toolkit, with an updated graphics stack (SkiaSharp 3). This platform upgrade is what the 3.0 version number marks; the app is meant to look and behave the same as before, on all platforms.
• Statistics chart. The books-per-year chart is now drawn with ScottPlot, replacing the previous charting library, and follows the active theme's colours.
• Cover previews load when you need them. Hovering a cover in the book list now fetches the full-size preview on demand instead of loading every cover up front, and the preview appears beside the thumbnail. With a library on a remote server, the first hover on a book may take a moment; after that it is instant.

Fixed

• BookDB no longer consumes CPU while sitting idle — a hidden progress indicator kept the renderer busy even when nothing was happening.
• Memory use with a large library is dramatically lower: the book list no longer keeps a decoded full-size cover image in memory for every book (a ~1000-book library with covers previously held on the order of a gigabyte; now it doesn't).
• Importing from Readerware (backup file or live database) and restoring a CSV archive no longer hold every cover image in memory at once — covers are now processed and released one batch at a time, so large libraries import and restore in steady memory.
• Restoring a backup into the same folder a second time no longer fails with "file already exists": the safety backup taken before a restore now gets a dated, auto-suffixed name, the same scheme manual backups use.
• Restoring a SQLite file backup on macOS failed with a "file in use" error. The restore now closes the database's open connections — and clears leftover write-ahead-log files — before replacing the library, on every platform.