feat(tests): integrate Playwright and Vitest for testing, add CI pipeline, and update dependencies

- Added Playwright configuration for end-to-end testing.
- Integrated Vitest for unit testing with setup files.
- Updated package.json scripts for testing commands.
- Created CI pipeline for automated testing and builds.
- Added various test cases for components and pages.
- Updated .gitignore to exclude Playwright and coverage.
- Enhanced ModsList component with additional class for styling.

src/tests/pages/routes.spec.ts

@@ -0,0 +1,9 @@
+import { expect, test } from '@playwright/test'
+
+test('all routes do not return 404', async ({ page }) => {
+  const routes = ['/', '/welcome', '/about', '/privacy-policy', '/download', '/donate', '/whatsnew']
+  for (const route of routes) {
+    const response = await page.goto(route)
+    expect(response?.status()).not.toBe(404)
+  }
+})