Reader: compare button next to Aa

A button beside Aa in the reader's top bar opens a Compare translations
sheet (pick the Bible to compare with, show/hide the differing-word
highlights). It shows as active while a comparison is on. The controls
moved out of the Aa sheet; "C" opens it from the keyboard.

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

src/pages/ReaderPage.jsx

@@ -15,6 +15,7 @@ import ReaderText from '../components/reader/ReaderText.jsx';
 import PlanStrip from '../components/reader/PlanStrip.jsx';
 import NavigatorSheet from '../components/reader/NavigatorSheet.jsx';
 import SettingsSheet from '../components/reader/SettingsSheet.jsx';
+import CompareSheet from '../components/reader/CompareSheet.jsx';
 import SearchSheet from '../components/reader/SearchSheet.jsx';
 import MarksSheet from '../components/reader/MarksSheet.jsx';
 import { useToast } from '../components/Toasts.jsx';
@@ -272,6 +273,7 @@ export default function ReaderPage() {
         if (e.key === '/') { e.preventDefault(); openSheet('search'); }
         else if (e.key === 'g' || e.key === 'G') { e.preventDefault(); openSheet('nav'); }
         else if (e.key === ',') { e.preventDefault(); openSheet('settings'); }
+        else if (e.key === 'c' || e.key === 'C') { e.preventDefault(); openSheet('compare'); }
         else if (e.key === 'f' || e.key === 'F') setChromeVisible((v) => !v);
         else if ((e.key === 'b' || e.key === 'B') && selectedKey) {
           readerBookmarks[selectedKey] ? removeBookmark(selectedKey, readerBookmarks[selectedKey]) : toggleReaderBookmark(selectedKey);
@@ -405,6 +407,7 @@ export default function ReaderPage() {
           onSearch={() => openSheet('search')}
           onBookmarks={() => openSheet('bookmarks')}
           bookmarkCount={bookmarkEntries.length + highlightEntries.length}
+          onCompare={() => openSheet('compare')} compareActive={!!parallelId}
           onSettings={() => openSheet('settings')}
           onDoneDrawing={readerDrawMode ? () => setReaderDrawMode(false) : undefined}
         />
@@ -558,6 +561,9 @@ export default function ReaderPage() {
         font={readerFont} onFont={setReaderFont}
         spacing={readerSpacing} onSpacing={setReaderSpacing}
         verseNumbers={readerVerseNumbers} onVerseNumbers={setReaderVerseNumbers}
+      />
+      <CompareSheet
+        open={sheet === 'compare'} onClose={closeSheet}
         translation={readerTranslation} parallel={parallelId} onParallel={setReaderParallel}
         showDiff={readerShowDiff} onShowDiff={setReaderShowDiff}
       />