Fix duplicate preference keys for custom HTTPS endpoints

Include httpBaseUrl in the fallback path of endpointDefaultPreferenceKey
so that multiple custom HTTPS endpoints (which share the same provider,
reachability, scheme, and label) produce distinct keys. This fixes:

- Duplicate React keys in the MenuItem map for pairing link copy options
- Multiple custom endpoints incorrectly showing the 'Default' badge when
  any one of them is set as the default

Author: cursoragent

apps/web/src/components/settings/ConnectionsSettings.tsx

@@ -290,7 +290,7 @@ function endpointDefaultPreferenceKey(endpoint: AdvertisedEndpoint): string {
     // Keep the stored preference stable even if a custom endpoint is malformed.
   }
 
-  return `${endpoint.provider.id}:${endpoint.reachability}:${scheme}:${endpoint.label}`;
+  return `${endpoint.provider.id}:${endpoint.reachability}:${scheme}:${endpoint.label}:${endpoint.httpBaseUrl}`;
 }
 
 function resolveAdvertisedEndpointPairingUrl(