fix: load .env.test in Playwright config for OPENAI_TEST_API_KEY

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

e2e/playwright.config.ts

@@ -1,4 +1,9 @@
 import { defineConfig } from '@playwright/test';
+import dotenv from 'dotenv';
+import path from 'path';
+
+// Load e2e/.env.test if it exists (contains OPENAI_TEST_API_KEY)
+dotenv.config({ path: path.resolve(__dirname, '.env.test') });
 
 /**
  * Playwright configuration for AI Weekly Synth E2E tests.