App quality: offline badge, per-note history, keyboard study mode, notes import

- Study cards say whether the Bible text works offline, with a button to save
  the missing book (notes are always kept on the device).
- Each note keeps its last 12 versions with Restore (History under each note).
- Keyboard-only study: 1/2/3 write in Observe/Interpret/Apply, C/W/X/P switch
  resource tabs, V compares, Esc leaves a note box; listed under "?".
- Export > Import notes: bring Word/Markdown/text notes into the matching
  chunks without overwriting anything; can mark them as not your own.

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

src/utils/noteHistory.test.js

@@ -0,0 +1,26 @@
+import { beforeEach, expect, test } from 'vitest';
+import { MAX_VERSIONS, listNoteVersions, recordNoteVersion } from './noteHistory.js';
+
+beforeEach(() => localStorage.clear());
+
+test('versions are kept newest first, and blanks and repeats are skipped', () => {
+  recordNoteVersion('c1', 'observation', 'first', 1);
+  recordNoteVersion('c1', 'observation', 'first', 2); // same as the newest
+  recordNoteVersion('c1', 'observation', '   ', 3); // blank
+  recordNoteVersion('c1', 'observation', 'second', 4);
+  expect(listNoteVersions('c1', 'observation').map((v) => v.text)).toEqual(['second', 'first']);
+  expect(listNoteVersions('c1', 'application')).toEqual([]);
+  expect(listNoteVersions('c2', 'observation')).toEqual([]);
+});
+
+test('only the latest versions are kept', () => {
+  for (let i = 0; i < MAX_VERSIONS + 5; i += 1) recordNoteVersion('c1', 'observation', `v${i}`, i);
+  const list = listNoteVersions('c1', 'observation');
+  expect(list).toHaveLength(MAX_VERSIONS);
+  expect(list[0].text).toBe(`v${MAX_VERSIONS + 4}`);
+});
+
+test('a damaged store reads as empty', () => {
+  localStorage.setItem('note-history:c1:observation', '{nope');
+  expect(listNoteVersions('c1', 'observation')).toEqual([]);
+});