build: configure Cloudflare Pages deployment

- Add wrangler CLI and workerd runtime as dev dependencies
- Configure nitro prerender with autoSubfolderIndex disabled for Pages
- Add Turnstile validation endpoint for server-side CAPTCHA verification
- Add baseline-browser-mapping for browser compatibility

wrangler.toml

@@ -0,0 +1,9 @@
+name = "phundrak-com-frontend"
+compatibility_date = "2025-01-01"
+pages_build_output_dir = "dist"
+
+# D1 Database binding for Nuxt Content
+[[d1_databases]]
+binding = "DB"
+database_name = "dev-phundrak-content"
+database_id = "91ad6cc9-c5ee-4d61-951c-1e74c77f6892"