chore: remove unused playwright config and debug scripts

Remove playwright.config.ts (no longer using Playwright for E2E),
and delete test-s3-playwright.js / test-s3-playwright-simple.js
(one-off S3 debug scripts).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

playwright.config.ts

@@ -1,23 +0,0 @@
-import { defineConfig } from '@playwright/test'
-
-export default defineConfig({
-  testDir: './tests/e2e',
-  timeout: 120000,
-  fullyParallel: false,
-  forbidOnly: !!process.env.CI,
-  retries: process.env.CI ? 2 : 0,
-  workers: 1,
-  reporter: 'html',
-  use: {
-    trace: 'on-first-retry',
-    screenshot: 'only-on-failure'
-  },
-
-  // Test configuration for Electron
-  projects: [
-    {
-      name: 'electron',
-      testMatch: '**/*.test.ts'
-    }
-  ]
-})