fix(backend): include interfaceName in ListNodes API response (#395)

- Add missing interfaceName field to node list API response map
- Fixes bug where interface name value disappears after page refresh
- Field is correctly saved to DB but was not returned in API response

Co-authored-by: Alex-WU-Gen-9-png <github@enomria0785.eu.org>

go-backend/internal/store/repo/repository.go

@@ -683,6 +683,7 @@ func (r *Repository) ListNodes() ([]map[string]interface{}, error) {
 			"remoteToken":               nullableString(n.RemoteToken),
 			"remoteConfig":              nullableString(n.RemoteConfig),
 			"expiryReminderDismissed":   n.ExpiryReminderDismissed,
+			"interfaceName":             nullableString(n.InterfaceName),
 		})
 	}
 	return items, nil