fix: respect RTL direction for reader arrow buttons and swipe navigation

Arrow buttons now swap next/previous in RTL mode. Swipe navigation
receives isRTL from parent state instead of creating its own independent
copy, so toggling direction takes effect immediately without reload.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/reader/PhotoswipeReader.tsx

@@ -76,6 +76,7 @@ export function PhotoswipeReader({ book, pages, onClose, nextBook }: BookReaderP
     onPreviousPage: handlePreviousPage,
     onNextPage: handleNextPage,
     pswpRef,
+    isRTL,
   });
 
   // Activer le zoom dans le reader en enlevant la classe no-pinch-zoom