fix(test): corrigir race condition no teste de persistência do swarm

Teste 'save and load state from disk' agora aguarda _pendingSave antes
de chamar _saveToDisk(), evitando escrita concorrente que corrompia JSON
(SyntaxError: Unexpected end of JSON input no CI)

Author: nikolasdehor

tests/core/orchestration/swarm-intelligence.test.js

@@ -950,7 +950,8 @@ describe('SwarmIntelligence', () => {
         content: 'works!',
       });
 
-      // Wait for async persistence
+      // Wait for all pending async writes, then do a final save
+      if (persisted._pendingSave) await persisted._pendingSave;
       await persisted._saveToDisk();
 
       // Load into fresh instance