fix: increase Node heap and timeout for Playwright webServer build

The e2e webServer builds the frontend via npm run build, which OOMs
on CI runners without --max-old-space-size=4096. Also increase timeout
from 120s to 180s to accommodate the larger heap build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/playwright.config.ts

@@ -38,10 +38,10 @@ export default defineConfig({
       },
     },
     {
-      command: 'npm run build && npm run preview -- --host 127.0.0.1 --port 4173',
+      command: 'NODE_OPTIONS="--max-old-space-size=4096" npm run build && npm run preview -- --host 127.0.0.1 --port 4173',
       url: frontendBaseUrl,
       reuseExistingServer: !process.env.CI,
-      timeout: 120_000,
+      timeout: 180_000,
       env: {
         ...process.env,
         VITE_API_URL: apiOrigin,