**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.

package.json

@@ -74,7 +74,8 @@
     "test:core": "vitest run tests/core.test.ts",
     "test:coverage": "vitest run --coverage",
     "test:size": "vitest run tests/package-size-limit.test.ts",
-    "test:all": "npm run build && vitest run"
+    "test:all": "npm run build && vitest run",
+    "test:report": "vitest run --reporter verbose"
   },
   "keywords": [
     "vector-database",
@@ -122,22 +123,25 @@
     "@rollup/plugin-node-resolve": "^15.2.3",
     "@rollup/plugin-replace": "^5.0.5",
     "@rollup/plugin-typescript": "^11.1.6",
+    "@types/express": "^5.0.3",
     "@types/jsdom": "^21.1.7",
     "@types/node": "^20.11.30",
     "@types/uuid": "^10.0.0",
     "@typescript-eslint/eslint-plugin": "^7.4.0",
     "@typescript-eslint/parser": "^7.4.0",
+    "@vitest/coverage-v8": "^3.2.4",
     "@vitest/ui": "^3.2.4",
     "eslint": "^8.57.0",
+    "express": "^5.1.0",
     "happy-dom": "^18.0.1",
     "jsdom": "^26.1.0",
+    "node-fetch": "^3.3.2",
     "puppeteer": "^22.5.0",
     "rollup": "^4.13.0",
     "rollup-plugin-terser": "^7.0.2",
     "tslib": "^2.6.2",
     "typescript": "^5.4.5",
-    "vitest": "^3.2.4",
-    "@vitest/coverage-v8": "^3.2.4"
+    "vitest": "^3.2.4"
   },
   "dependencies": {
     "@aws-sdk/client-s3": "^3.540.0",