fix: service_spec_gen skip 404 services gracefully instead of panic

universal_rebuild/tools/service_spec_gen/generate_service_spec.go

@@ -72,7 +72,8 @@ func main() {
 		// Fetch service metadata and the operation list.
 		info, err := client.getService(svc.ID)
 		if err != nil {
-			panic(err)
+			fmt.Fprintf(os.Stderr, "WARNING: service %d (%s) skipped: %v\n", svc.ID, svc.Name, err)
+			continue
 		}
 		// Prefer the explicit name from services_list.txt; otherwise derive from API.
 		name := strings.TrimSpace(svc.Name)