Convert Cloudflare Worker to Cloudflare Pages

This commit converts the entire Xget application from a Cloudflare Worker
to a Cloudflare Page, enabling static asset hosting while maintaining all
existing functionality.

Changes:
- Add functions/[[path]].js: Catch-all Pages Function handler
- Add public/index.html: Landing page with Xget information
- Update src/index.js: Export handleRequest for Pages Function import
- Update wrangler.toml: Configure for Pages deployment
- Update package.json: Change scripts to use Pages commands
- Update vitest.config.js: Include functions/ in coverage
- Update .github/workflows/depoly.yml: Deploy to Pages
- Update documentation: CLAUDE.md, README.md, README.en.md

The conversion maintains full backward compatibility with existing tests
and functionality. All caching strategies, security headers, and protocol
handling remain unchanged.

.github/workflows/depoly.yml

@@ -1,4 +1,4 @@
-name: Deploy Worker
+name: Deploy to Cloudflare Pages
 permissions:
   contents: read
 
@@ -25,8 +25,9 @@ jobs:
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v5
-      - name: Deploy Worker
+      - name: Deploy to Cloudflare Pages
         uses: cloudflare/wrangler-action@v3
         with:
           apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
           accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+          command: pages deploy