Add test coverage for assets/app.js

- Test that initMobileMenu and initTabs are called on DOMContentLoaded

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

tests/js/app.test.js

@@ -0,0 +1,26 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+vi.mock('../../assets/modules/mobile-menu.js', () => ({
+    initMobileMenu: vi.fn(),
+}))
+
+vi.mock('../../assets/modules/tabs.js', () => ({
+    initTabs: vi.fn(),
+}))
+
+import { initMobileMenu } from '../../assets/modules/mobile-menu.js'
+import { initTabs } from '../../assets/modules/tabs.js'
+
+describe('app.js', () => {
+    beforeEach(() => {
+        vi.clearAllMocks()
+    })
+
+    it('calls initMobileMenu and initTabs on DOMContentLoaded', async () => {
+        await import('../../assets/app.js')
+        document.dispatchEvent(new Event('DOMContentLoaded'))
+
+        expect(initMobileMenu).toHaveBeenCalled()
+        expect(initTabs).toHaveBeenCalled()
+    })
+})