v2.0.0

Added

• PostgreSQL database support: BookDB can now keep your library on a PostgreSQL server instead of the local file, so the same catalog is reachable from more than one machine. SQLite stays the default and needs no setup — remote databases are entirely opt-in. PostgreSQL 12 or later is required (the full-text search column uses a stored generated column added in PostgreSQL 12); Test connection reports a clear message and refuses to proceed against an older server.
• Settings → Database tab to choose the backend and enter the server details (host, port, database, user, password, TLS mode), with a Test connection button that reports the server version and book count before you commit. Switching the active database restarts the app to load it.
• Passwords for remote databases are stored in your operating system's secret store (Windows Credential Manager, macOS Keychain, or Linux Secret Service) — never in plain text. On a system with no secret store available, the PostgreSQL option is disabled with an explanation and SQLite remains available.
• Move library (Tools → Maintenance): copy your entire catalog between SQLite and PostgreSQL in either direction. It takes a safety backup first, checks the target isn't about to be overwritten unknowingly, shows per-table progress, verifies every row count matches, and can switch the active database to the target when it finishes.
• Restore from a CSV archive backup: it replaces the current library, always taking a safety backup of the live database first, and runs the whole restore as one transaction so a failure leaves your data untouched. When the backup names a different PostgreSQL server, you can restore directly into that server so the data and its connection settings land together.
• Multi-client warning: when using a remote database, BookDB notices if another client appears to be connected and offers to quit rather than risk two clients writing at once (with a "connect anyway" override). A crashed client ages out automatically and never locks you out.
• Connection-loss handling for remote databases: a clear dialog if the server can't be reached at startup (with Retry / open Settings / Quit), automatic reconnection if the connection drops mid-session, and a Retry / Discard prompt if a save can't reach the server — so your edits are never silently lost.
• The Maintenance tools (Tools → Maintenance) now adapt to the active database: on PostgreSQL they run a server-side connectivity and sanity check, VACUUM (ANALYZE), and report the database size, in place of the SQLite-only integrity check and file repair.

Changed

• Auto-backup on close now uses the engine-neutral CSV archive when the active database is remote (the file-copy backup remains for local SQLite).