Update e2e tests and mocks for locale-based routing

- Adjusted assertions and navigation tests to include `/en` locale prefix for consistency.
- Updated next-intl and components-i18n mocks to support locale handling in tests.
- Renamed "Components" link and related references to "Design System" in homepage tests.
- Disabled typing delay in debounce test for improved test reliability.

frontend/e2e/settings-navigation.spec.ts

@@ -18,7 +18,7 @@ test.describe('Settings Navigation', () => {
   test('should navigate from home to settings profile', async ({ page }) => {
     // Start at home page (auth already cached in storage state)
     await page.goto('/en');
-    await expect(page).toHaveURL('/');
+    await expect(page).toHaveURL('/en');
 
     // Navigate to settings/profile
     await page.goto('/en/settings/profile');
@@ -33,7 +33,7 @@ test.describe('Settings Navigation', () => {
   test('should navigate from home to settings password', async ({ page }) => {
     // Start at home page (auth already cached in storage state)
     await page.goto('/en');
-    await expect(page).toHaveURL('/');
+    await expect(page).toHaveURL('/en');
 
     // Navigate to settings/password
     await page.goto('/en/settings/password');