Add Insights, Observe-first, compare, handout layouts, richer search, backup nudge

- Commentary and study aids wait for 15 words of your own Observe notes.
- Insights page: this week's own work, themes across studies, words you keep
  studying, what slipped in recalls, open follow-ups.
- Recall can record what slipped; session notes (teach it back, who came,
  group notes, follow-ups); "Pray about this" from Apply.
- Compare any two passages side by side.
- Handout layouts: standard, questions only, large print, note-taking.
- Search understands "in <book>", "last week/month/year" and a year.
- Home shows the last backup age and nudges after two weeks.
- Phone: the stage bar scrolls instead of clipping Script and Export.

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

src/utils/projectDiff.js

@@ -2,6 +2,7 @@
 const FIELD_NAMES = {
   observation: 'Observe', interpretation: 'Interpret', application: 'Apply', generalNotes: 'Background', finalScript: 'Script',
   discussionQuestions: 'Questions', episodeNumber: 'Session number', episodeTitle: 'Session title',
+  teachBack: 'Teach it back', attendees: 'Who came', groupNotes: 'Group notes',
 };
 const same = (a, b) => JSON.stringify(a ?? '') === JSON.stringify(b ?? '');