Add CLI backup commands and update restore API
Remove the sandbox id query param from restoreBackup lexicons/types and
use input.backupId instead. Update the XRPC handler to query the
backups table (left-joining sandboxes) and adjust the not-found check.
Add CLI backup command stubs (create, restore, list) and wire them into
the CLI. Minor schema/formatting tidy-up for backups id field.