fix: fail-fast in Playwright test runner — exit immediately on first failure

The test() helper was catching errors and collecting them into results[],
only checking for failures after all tests completed. This meant the runner
kept going through remaining tests even after a failure, wasting CI time
and obscuring the root cause.

Now process.exit(1) is called immediately when a test fails, giving true
fail-fast behavior.

test-e2e-playwright.js

@@ -17,6 +17,8 @@ async function test(name, fn) {
   } catch (err) {
     results.push({ name, pass: false, error: err.message });
     console.log(`  \u274c ${name}: ${err.message}`);
+    console.log(`\nFail-fast: stopping after first failure.`);
+    process.exit(1);
   }
 }