Version history, notes on highlights and bookmarks, "you've studied this", prayer journal

- Earlier versions of a study: the server keeps compressed copies (about one per ten minutes of
  editing, the latest 30); Export shows what differs and puts one back (the replaced copy is kept)
- Notes on highlights and bookmarks: synced, merged without loss, in exports and backups
- Reader verse panel lists your studies and chunks that cover the verse, and opens them
- Prayer journal: requests, who for, linked verses, days prayed, answers; synced, in backups
  and the account export; daily prayer reminder through ntfy
- TODO.md lists the ideas not built yet

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

server/accountExport.js

@@ -17,11 +17,13 @@ export function buildAccountExport(user, store, now = new Date()) {
     projects: store.projects(),
     reader: {
       bookmarks: marks.bookmarks ?? {},
+      bookmarkNotes: marks.bookmarkNotes ?? {},
       highlights: marks.highlights ?? [],
       colorLabels: prefs.colorLabels?.v ?? {},
       ink: store.ink() ?? {},
     },
     readingHistory: store.history?.() ?? { chapters: {}, days: [] },
+    prayers: store.prayers?.() ?? [],
     readingPlans: {
       progress: plans.progress ?? [],
       customPlans: plans.customPlans ?? [],