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/backup.test.js

@@ -68,3 +68,13 @@ test('prayers are in the backup, deleted ones are not, and they survive validati
   expect(checked.backup.prayers[0].text).toBe('Peace');
   expect(validateBackup({ app: 'bible-study-project', version: 1, prayers: [{ id: 'x' }, 5, { id: 'y', text: '  ' }] }).backup.prayers).toEqual([]);
 });
+
+import { backupAge } from './backup.js';
+
+test('the backup age says how long ago, and flags a long gap', () => {
+  const now = 1_000_000_000_000;
+  expect(backupAge(null, now)).toMatchObject({ stale: true });
+  expect(backupAge(now - 3600_000, now)).toEqual({ text: 'Backed up today', stale: false });
+  expect(backupAge(now - 5 * 86400000, now)).toEqual({ text: 'Last backup 5 days ago', stale: false });
+  expect(backupAge(now - 20 * 86400000, now).stale).toBe(true);
+});