Fix missing fqn variable in handleHostService

- Extract serviceFqn from publishResult for ICE candidate operations
- Fixes "ReferenceError: fqn is not defined" error

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/App.jsx

@@ -428,6 +428,9 @@ export default function App() {
         ttl: 300000, // 5 minutes
       });
 
+      // Get the full service FQN for ICE candidate operations
+      const fqn = publishResult.serviceFqn;
+
       // Map offerIds to peer connections and setup ICE handlers
       const offerMapping = {};
       const hostConnMap = {};