chore: migrate config to TypeScript

Updated config utility modules to .ts, added types to them, and updated
imports depending on those.

src/App.vue

@@ -15,7 +15,7 @@ limitations under the License.
 -->
 
 <script setup>
-import { LANGUAGE_PATH } from './config/featureSettings.js';
+import { LANGUAGE_PATH } from './config/featureSettings';
 import AppFooter from './features/footer/components/AppFooter.vue';
 import AppNavbar from './features/nav/components/AppNavbar.vue';
 import { useSettings } from './features/settings/composables/useSettings.js';

src/config/env.ts

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-export const getAssetsUrl = function getAssetsUrl() {
+export const getAssetsUrl = function getAssetsUrl(): string {
     return new URL(
         `${import.meta.env.VITE_ASSETS_BUILD_ID}/`,
         import.meta.env.VITE_ASSETS_BASE_URL,

src/features/i18n/components/__tests__/LanguageSwitchButton.test.js

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import LanguageSwitchButton from '../LanguageSwitchButton.vue';
-import { LANGUAGE_PATH } from '@/config/featureSettings.js';
+import { LANGUAGE_PATH } from '@/config/featureSettings';
 import { useSettings } from '@/features/settings/composables/useSettings.js';
 import { mountComponent } from '@/test-utils/mountComponent.js';
 import { describe, expect, test } from 'vitest';