perf(web): self-host Font Awesome instead of cdnjs CDN

Replace the external cdnjs.cloudflare.com <link> with a bundled
npm import so FA CSS+fonts ship as static assets through the
same Cloudflare CDN that serves the app — eliminates an extra
DNS lookup and third-party CDN dependency, improves reliability
for China users.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -21,6 +21,7 @@
     "deploy:cf": "opennextjs-cloudflare deploy"
   },
   "dependencies": {
+    "@fortawesome/fontawesome-free": "6.5.1",
     "@supabase/ssr": "^0.12",
     "@supabase/supabase-js": "^2.108",
     "drizzle-orm": "^0.45.2",