initialize Electron desktop app and remove unused files

playwright.electron.config.ts

@@ -0,0 +1,9 @@
+import { defineConfig } from '@playwright/test'
+
+export default defineConfig({
+  testDir: './tests/electron',
+  workers: 1,
+  timeout: 120_000,
+  reporter: 'list',
+  use: { trace: 'retain-on-failure' },
+})