feat: add keyboard shortcuts button and show/hide toolbar labels option

- Implemented a keyboard shortcuts button in the navigation rail.
- Added a setting to toggle the visibility of toolbar labels in appearance settings.
- Updated the email context menu to streamline actions for archiving, deleting, and marking emails as read/unread.
- Enhanced the email viewer with improved spam handling and read state toggling.
- Updated localization files to include new strings for keyboard shortcuts and toolbar labels.

app/[locale]/page.tsx

@@ -941,6 +941,7 @@ export default function Home() {
               quota={quota}
               isPushConnected={isPushConnected}
               onLogout={handleLogout}
+              onShowShortcuts={() => setShowShortcutsModal(true)}
             />
           </div>
         )}