add highContrastMode to type Settings

src/lib/stores/index.ts

@@ -142,6 +142,7 @@ type Settings = {
 	audio?: AudioSettings;
 	showUsername?: boolean;
 	notificationEnabled?: boolean;
+	highContrastMode?: boolean;
 	title?: TitleSettings;
 	splitLargeDeltas?: boolean;
 	chatDirection: 'LTR' | 'RTL' | 'auto';