Remove process.emit warning suppression hack from Playwright config

The Node 25 localStorage warning from MSW broke vue-tsc type-check
because the override signature was incompatible with the Signals type.

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

frontend/playwright.config.ts

@@ -1,15 +1,5 @@
 import { defineConfig, devices } from '@playwright/test'
 
-// Suppress Node 25 warning from MSW's cookieStore accessing native localStorage
-// without --localstorage-file being set. Harmless — MSW doesn't need file-backed storage.
-const originalEmit = process.emit.bind(process)
-process.emit = function (event: string, ...args: unknown[]) {
-  if (event === 'warning' && args[0] instanceof Error && args[0].message.includes('--localstorage-file')) {
-    return false
-  }
-  return originalEmit(event, ...args)
-} as typeof process.emit
-
 export default defineConfig({
   testDir: './e2e',
   fullyParallel: true,