fix: resolver ids de usuarios con IdentityService al devolver resultados

Co-authored-by: aider (openrouter/openai/gpt-5) <aider@aider.chat>

src/services/group-sync.ts

@@ -417,7 +417,11 @@ export class GroupSyncService {
 						if (!norm) continue;
 						result.push({ userId: norm, isAdmin });
 					}
-					return result;
+					const resolved = (() => {
+						const map = IdentityService.resolveMany(result.map(r => r.userId));
+						return result.map(r => ({ userId: map.get(r.userId) || r.userId, isAdmin: r.isAdmin }));
+					})();
+					return resolved;
 				}
 				// Si no viene en el formato esperado, caemos al plan B
 				console.warn('⚠️ /group/participants responded without participants array, falling back to fetchAllGroups');