fix: update portal link checker labels to match actual HTML

- Update navbar link expectations to match actual rendered text:
  - FRBR → FR
  - Muldicat → MULDICAT
  - Unimarc → UNIMARC
- Addresses ongoing link check failures in portal E2E tests
- Links checker now validates against actual navigation labels

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: jonphipps

scripts/check-portal-homepage-links.mjs

@@ -26,10 +26,10 @@ async function checkLinks(targetUrl, currentEnv) {
 
     { text: 'Navbar ISBDM', type: 'navExternal', toSite: 'ISBDM' },
     { text: 'Navbar LRM', type: 'navExternal', toSite: 'LRM' },
-    { text: 'Navbar FRBR', type: 'navExternal', toSite: 'FRBR' },
+    { text: 'Navbar FR', type: 'navExternal', toSite: 'FRBR' },
     { text: 'Navbar ISBD', type: 'navExternal', toSite: 'isbd' },
-    { text: 'Navbar Muldicat', type: 'navExternal', toSite: 'muldicat' },
-    { text: 'Navbar Unimarc', type: 'navExternal', toSite: 'unimarc' },
+    { text: 'Navbar MULDICAT', type: 'navExternal', toSite: 'muldicat' },
+    { text: 'Navbar UNIMARC', type: 'navExternal', toSite: 'unimarc' },
 
     { text: 'Footer ISBDM', type: 'footer', toSite: 'ISBDM' },
     { text: 'Footer LRM', type: 'footer', toSite: 'LRM' },