[LICENSE] relicense project under MPL 2.0

relicensed due to GitHub's Copilot push. details in README.md.

tests/desktop.test.ts

@@ -1,3 +1,9 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public License,
+ * v. 2.0. If a copy of the MPL was not distributed with this file, You can
+ * obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
 import { expect, test } from '@playwright/test';
 
 test('desktop page has nav tree', async ({ page }) => {

tests/general.test.ts

@@ -1,3 +1,9 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public License,
+ * v. 2.0. If a copy of the MPL was not distributed with this file, You can
+ * obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
 import { expect, test } from '@playwright/test';
 
 test('page has headline', async ({ page }) => {

tests/mobile.test.ts

@@ -1,3 +1,9 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public License,
+ * v. 2.0. If a copy of the MPL was not distributed with this file, You can
+ * obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
 import { expect, test } from '@playwright/test';
 
 import UserAgent from 'user-agents';