Companion to colibri fix/clawdie-db-path. The rc.d default already derives
clawdie_db_path from clawdie_data_dir, but write it explicitly into the staged
rc.conf (and the rc.conf.sample) so the operator can see the DB lives in
clawdie's own dir (/var/db/clawdie/clawdie.sqlite), not the colibri daemon's.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>