test(e2e): wait for locale navigation to complete

Locale switch can take longer in dev; wait explicitly for /de URL after click.

Co-authored-by: dennis <dennis@konkol.net>

e2e/i18n.spec.ts

@@ -10,8 +10,10 @@ test.describe("i18n routing", () => {
       // Verify an EN label is present before switching (nav.home)
       await expect(page.getByRole("link", { name: "Home" })).toBeVisible();
 
-      await deButton.click();
-      await expect(page).toHaveURL(/\/de(\/|$)/);
+      await Promise.all([
+        page.waitForURL(/\/de(\/|$)/, { timeout: 30000 }),
+        deButton.click(),
+      ]);
 
       // Verify the nav label updates after switching
       await expect(page.getByRole("link", { name: "Start" })).toBeVisible();