Move the mail queue under /data so recreate no longer drops deferred mail, and archive data/, compose, .env, and certs/ together for restore on a fresh host.
Co-authored-by: Cursor <cursoragent@cursor.com>
Lay out view, auth, validate, and handlers under internal/web while keeping
the cmd/panel API unchanged; update roadmap and changelog for web-split closure.
Co-authored-by: Cursor <cursoragent@cursor.com>