feat: merge PR #511 - display epub metadata on Recents

Integrates upstream PR #511 changes while preserving local delete/archive
functionality. Key changes:

- Add RecentBook struct with path, title, author fields
- Update RecentBooksStore to store and serialize metadata
- Implement version migration for existing recent.bin files
- Update MyLibraryActivity to display two-line items (title + author)
- Update EpubReaderActivity and XtcReaderActivity to pass metadata

Maintains backwards compatibility with delete/archive feature from
local commit d5a9873.

src/activities/reader/EpubReaderActivity.cpp

@@ -82,7 +82,7 @@ void EpubReaderActivity::onEnter() {
   // Save current epub as last opened epub and add to recent books
   APP_STATE.openEpubPath = epub->getPath();
   APP_STATE.saveToFile();
-  RECENT_BOOKS.addBook(epub->getPath());
+  RECENT_BOOKS.addBook(epub->getPath(), epub->getTitle(), epub->getAuthor());
 
   // Trigger first update
   updateRequired = true;