Fix unread count taskbar badge for Windows

ts/util/unreadIcon.ts

@@ -0,0 +1,26 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { join } from 'path';
+import type { NativeImage } from 'electron';
+import { nativeImage } from 'electron';
+
+export function getUnreadIcon(unreadCount: number): NativeImage {
+  const filename =
+    unreadCount > 9 ? '9-plus.png' : `${String(unreadCount)}.png`;
+  const path = join(__dirname, '..', '..', 'images', 'unread-icon', filename);
+  // if path does not exist, this returns an empty NativeImage
+  return nativeImage.createFromPath(path);
+}
+
+export function getMarkedUnreadIcon(): NativeImage {
+  const path = join(
+    __dirname,
+    '..',
+    '..',
+    'images',
+    'unread-icon',
+    'marked-unread.png'
+  );
+  return nativeImage.createFromPath(path);
+}