**test(api): add integration tests for API endpoints and core functionality**

- **Integration Tests**:
  - Introduced `api-integration.test.ts` to validate API functionality:
    - Verifies text insertion, vector embedding generation, and search operations.
    - Confirms HNSW index correctness for vector similarity search.
    - Ensures no dimensional mismatches in embeddings.

- **Test Server**:
  - Added test server utilizing Express for endpoint simulation (`/insert` and `/search/text`).

- **Dependencies**:
  - Introduced `express` and `node-fetch` as new dependencies for testing purposes.

- **Vitest Fix**:
  - Updated `vitest.config.ts` to resolve the `process.memoryUsage` error by setting `logHeapUsage: false`.

- **Package Updates**:
  - Modified `package-lock.json` to include newly added dependencies and updates.

**Purpose**: Guarantees the stability of core API endpoints and vector-related functionality, ensuring reliable behavior for end-to-end scenarios.

test-fix.js

@@ -0,0 +1,20 @@
+// Simple test script to verify the FileSystemStorage fix
+const { createStorage } = require('./dist/unified.js');
+
+async function testFileSystemStorage() {
+  try {
+    console.log('Creating storage with forceFileSystemStorage: true');
+    const storage = await createStorage({ forceFileSystemStorage: true });
+    console.log('Storage created successfully');
+    
+    console.log('Initializing storage');
+    await storage.init();
+    console.log('Storage initialized successfully');
+    
+    console.log('Test passed: No TypeError about undefined path.join');
+  } catch (error) {
+    console.error('Test failed with error:', error);
+  }
+}
+
+testFileSystemStorage();