Remove podcast checklist backend, calendar events and reminder emails; v2.14.3

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server/routes/admin-backup.js

@@ -24,7 +24,6 @@ import {
   loadDownloadCountsFromDisk,
   loadQrCodesFromDisk,
   loadEpisodePlaysFromDisk,
-  loadPodcastChecklistFromDisk,
   loadAnalyticsEventsFromDisk,
   createBackupSnapshot,
   refreshContentCaches,
@@ -105,7 +104,6 @@ async function flushPendingWrites() {
     state.draftQuestionsWritePromise,
     state.replyTemplatesWritePromise,
     state.replyHistoryWritePromise,
-    state.podcastChecklistWritePromise,
     state.studyUsersWritePromise,
     state.studyCommunityWritePromise,
     state.studyRemindersWritePromise,
@@ -148,7 +146,6 @@ async function reloadStateFromDisk() {
     loadDownloadCountsFromDisk(),
     loadQrCodesFromDisk(),
     loadEpisodePlaysFromDisk(),
-    loadPodcastChecklistFromDisk(),
     loadAnalyticsEventsFromDisk(),
     refreshContentCaches(),
   ])