Bump migration version to 247 and add a migration that creates performance indexes for LoTW workflows (idx_lotw_qslrdate, idx_lotw_qsos_to_upload, idx_lotw_confirmation_match) to speed common queries. Refactor Lotw controller to collect records in memory, build rows for rendering, and perform a single batch confirmation update via a new Logbook_model::lotw_update_batch() method instead of many individual updates. Implement lotw_update_batch() to look up matching QSOs, perform update_batch() calls, and separately update gridsquares/distances using the Qra library. Simplify LotwCert::toggle_archive_certificate() to toggle archived state with a single UPDATE and return the resulting status.
Added 'archived' => 0 to the queries in lotw_cert_expired and lotw_cert_expiring methods to ensure only active certificates are considered when checking for expired or expiring LOTW certificates.
Introduces an 'archived' boolean column to the lotw_certs table via migration, adds model and controller logic to toggle archive status, and updates the view to display and allow archiving/unarchiving of certificates. This enables users to mark LoTW certificates as archived for better management.
