Simplify test-runner config to minimal working version

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

.storybook/test-runner.ts

@@ -1,24 +1,12 @@
 import type { TestRunnerConfig } from '@storybook/test-runner';
 
 const config: TestRunnerConfig = {
-  // Hook that is executed once before all tests
-  async setup() {
-    // Global setup if needed
-  },
-  
-  // Hook that is executed before the test runner starts running tests
   async preVisit(page) {
-    // Set up any global variables or configurations needed for tests
+    // Inject __test global to prevent ReferenceError during test execution
     await page.evaluate(() => {
-      // Define __test global if it's being referenced by test infrastructure
       (window as any).__test = true;
     });
   },
-  
-  // Hook that is executed after the test runner finishes running tests  
-  async postVisit(page) {
-    // Clean up if needed
-  },
 };
 
 export default config;