fix: use vitest imports instead of jest in integration tests

tests/integration/database/performance.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeEach, afterEach } from '@jest/globals';
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
 import * as Database from 'better-sqlite3';
 import { NodeRepository } from '../../../src/database/node-repository';
 import { TemplateRepository } from '../../../src/templates/template-repository';