**test(tests): add comprehensive test suite for Brainy functionality**

- **New Tests Added**:
  - Introduced multiple test suites covering core functionalities (`core.test.ts`), vector operations (`vector-operations.test.ts`), Node.js environment (`environment.node.test.ts`), browser setup (`environment.browser.test.ts`), and TensorFlow.js-specific behaviors (`tensorflow-patch.test.ts`).
  - Added performance, scalability, and error-handling tests to ensure robust validation of vector addition, search, and text embedding functionalities.
  - Introduced setup utilities (`tests/setup.ts`) and standardized test utilities for creating predictable test cases.

- **Configuration**:
  - Created `vitest.config.ts` for custom test configurations, including support for modern test environments (`jsdom`, `happy-dom`) and extended timeouts for asynchronous operations.

- **Validation**:
  - Includes compatibility checks for TensorFlow.js imports and ensures proper handling of `TextEncoder`/`TextDecoder` in Node.js environments.

This commit significantly enhances the testing coverage and structure, ensuring Brainy functionality is robust, cross-platform, and aligned with evolving reliability standards.

test-tensorflow-import.js

@@ -0,0 +1,24 @@
+const { applyTensorFlowPatch } = require('./src/utils/textEncoding.js')
+
+console.log('Before patch:')
+console.log('global.TextEncoder:', typeof global.TextEncoder)
+console.log('global.__TextEncoder__:', typeof global.__TextEncoder__)
+
+applyTensorFlowPatch()
+
+console.log('After patch:')
+console.log('global.TextEncoder:', typeof global.TextEncoder)
+console.log('global.__TextEncoder__:', typeof global.__TextEncoder__)
+
+// Try to import tensorflow
+async function testTensorFlow() {
+  try {
+    console.log('Importing TensorFlow...')
+    const tf = await import('@tensorflow/tfjs-core')
+    console.log('TensorFlow imported successfully:', tf.version)
+  } catch (error) {
+    console.error('TensorFlow import failed:', error.message)
+  }
+}
+
+testTensorFlow()