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/components/ShortcutsHelp.jsx

@@ -22,6 +22,10 @@ const BY_PAGE = {
   ],
   study: [
     ['← →', 'Previous / next chunk'],
+    ['1  2  3', 'Write in Observe / Interpret / Apply'],
+    ['Esc', 'Leave a note box (then keys work again)'],
+    ['C  W  X  P', 'Commentary / Word study / Cross-refs / People & places'],
+    ['V', 'Compare passages or translations'],
   ],
 };