refactor(testing): migrate from Jest to Vitest for testing framework

DEVELOPMENT.md

@@ -14,3 +14,25 @@
 ### GitHub REST API v3
 
 - https://developer.github.com/v3/
+
+## Development Instructions
+
+### Running Tests
+
+This project uses [Vitest](https://vitest.dev/) for testing. To run the tests, use the following command:
+
+```bash
+npm run test
+```
+
+Vitest will execute all test files and provide a detailed report of the results.
+
+### Generating Coverage Reports
+
+To generate a test coverage report, use the following command:
+
+```bash
+npm run test:coverage
+```
+
+The coverage report will be available in the `coverage` directory.