Slimbooks v2.0.0

Package dist/ alone, and back up the database from where it now lives

The release job still tar'd server/dist, which 2.0.0 removed, so packaging
failed with "Cannot stat: No such file or directory" after a green build. The
build emits dist/client and dist/server, so dist alone covers both halves.

The Raspberry Pi backup script had the same stale path. That one failed
quietly: it tested for a file that no longer exists and skipped the backup, so
an operator would have been told nothing while getting no database backup at
all. It now reads DATA_DIR, warns when it finds nothing, and prefers
sqlite3 .backup over cp — copying a WAL database out from under a running
server can capture a torn state.

Co-Authored-By: Claude Opus 5 noreply@anthropic.com