feat: configure Jest testing infrastructure

- Update Jest config with module name mapping for uuid and node-fetch
- Add Babel transform for mixed JS/TS support
- Configure transformIgnorePatterns for ES modules
- Add comprehensive test mocks for uuid and node-fetch
- Setup import.meta environment variables for Jest compatibility
- Increase test timeout to 30 seconds for integration tests

tests/__mocks__/uuid.js

@@ -0,0 +1,4 @@
+// Mock for uuid module
+module.exports = {
+  v4: jest.fn(() => '12345678-1234-1234-1234-123456789012'),
+};