feat: add long-press Confirm for book management in file browser and recents

Long-pressing Confirm on a book file in MyLibraryActivity or
RecentBooksActivity opens the BookManageMenuActivity popup with
Archive/Delete/Delete Cache/Reindex options. Actions are executed
via BookManager and the file list is refreshed afterward.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/activities/home/RecentBooksActivity.h

@@ -18,12 +18,17 @@ class RecentBooksActivity final : public ActivityWithSubactivity {
   // Recent tab state
   std::vector<RecentBook> recentBooks;
 
+  // Long-press state
+  bool ignoreNextConfirmRelease = false;
+  static constexpr unsigned long LONG_PRESS_MS = 700;
+
   // Callbacks
   const std::function<void(const std::string& path)> onSelectBook;
   const std::function<void()> onGoHome;
 
   // Data loading
   void loadRecentBooks();
+  void openManageMenu(const std::string& bookPath);
 
  public:
   explicit RecentBooksActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,