Feature: followers list with delivery health for cleanup
Adds a /followers page (new Fediverse tab) listing remote accounts that
follow you, each with its last SUCCESSFUL delivery timestamp so dead accounts
surface for manual pruning. New ap_followers columns last_delivery_at /
last_error_at (additive migration) are stamped in deliverWithRetry and the
retry-queue worker on success / final give-up. Never-delivered and failing
accounts sort to the top and are highlighted; a Remove button drops the local
follower row after a manual check. i18n added for NL/EN/DE.
Co-Authored-By: Claude Opus 4.8 <noreply@…>