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.

stores/settings-store.ts

@@ -97,6 +97,7 @@ interface SettingsState {
 
   // Layout
   toolbarPosition: ToolbarPosition;
+  showToolbarLabels: boolean;
 
   // Experimental
   senderFavicons: boolean;
@@ -175,6 +176,7 @@ const DEFAULT_SETTINGS = {
 
   // Layout
   toolbarPosition: 'top' as ToolbarPosition,
+  showToolbarLabels: true,
 
   // Experimental
   senderFavicons: true,