Refactor test setup: standardize scrollIntoView function formatting and add Vitest type definitions

frontend/src/setupTests.ts

@@ -23,7 +23,7 @@ window.matchMedia =
   };
 
 // Mock scrollIntoView - not implemented in JSDOM but used by Ionic components
-Element.prototype.scrollIntoView = function() {};
+Element.prototype.scrollIntoView = function () {};
 
 // Run before each test SUITE
 beforeAll(() => {

frontend/src/types/vitest.d.ts

@@ -0,0 +1,27 @@
+import 'vitest';
+
+// Extend the expect interface with testing-library matchers
+declare global {
+  // Add typings for Vitest global functions
+  const describe: typeof import('vitest')['describe'];
+  const it: typeof import('vitest')['it'];
+  const test: typeof import('vitest')['test'];
+  const expect: typeof import('vitest')['expect'];
+  const vi: typeof import('vitest')['vi'];
+  const beforeEach: typeof import('vitest')['beforeEach'];
+  const afterEach: typeof import('vitest')['afterEach'];
+  const beforeAll: typeof import('vitest')['beforeAll'];
+  const afterAll: typeof import('vitest')['afterAll'];
+
+  // Extend the globalThis interface to allow assigning Vitest functions
+  interface Window {
+    expect: typeof import('vitest')['expect'];
+    afterEach: typeof import('vitest')['afterEach'];
+    beforeEach: typeof import('vitest')['beforeEach'];
+    describe: typeof import('vitest')['describe'];
+    it: typeof import('vitest')['it'];
+    vi: typeof import('vitest')['vi'];
+    beforeAll: typeof import('vitest')['beforeAll'];
+    afterAll: typeof import('vitest')['afterAll'];
+  }
+}