fix(ci): resolve @fortawesome/fontawesome-free from public npm registry

The frontend deps bump regenerated ui/package-lock.json with the
@fortawesome/fontawesome-free tarball resolved from npm.fontawesome.com
(per the developer's scoped ~/.npmrc), which requires auth. CI has no
FontAwesome token, so `npm ci` failed with E401.

The free package is also published to the public registry with an
identical tarball/integrity, so pin @fortawesome to registry.npmjs.org
via ui/.npmrc and repoint the lockfile. Verified `npm ci` + build now
succeed with no token.

ui/.npmrc

@@ -0,0 +1,4 @@
+# Resolve the FontAwesome *free* package from the public npm registry rather than
+# the authenticated npm.fontawesome.com. This lets `npm ci` work in CI without a
+# FontAwesome token (the free package is published to registry.npmjs.org too).
+@fortawesome:registry=https://registry.npmjs.org/

ui/package-lock.json

@@ -132,7 +132,7 @@
     },
     "node_modules/@fortawesome/fontawesome-free": {
       "version": "7.2.0",
-      "resolved": "https://npm.fontawesome.com/@fortawesome/fontawesome-free/-/fontawesome-free-7.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/@fortawesome/fontawesome-free/-/fontawesome-free-7.2.0.tgz",
       "integrity": "sha512-3DguDv/oUE+7vjMeTSOjCSG+KeawgVQOHrKRnvUuqYh1mfArrh7s+s8hXW3e4RerBA1+Wh+hBqf8sJNpqNrBWg==",
       "dev": true,
       "license": "(CC-BY-4.0 AND OFL-1.1 AND MIT)",