Replace jest.config.mjs with jest.config.js for TypeScript support

Author: billytrend-cohere

.fernignore

@@ -17,3 +17,4 @@ src/ClientV2.ts
 src/CustomClient.ts
 src/core/form-data-utils/FormDataWrapper.ts
 tests/unit/form-data-utils/formDataWrapper.test.ts
+jest.config.mjs

jest.config.js

@@ -0,0 +1,7 @@
+module.exports = {
+  preset: 'ts-jest',
+  transform: {
+    '^.+\\.(ts|tsx)?$': 'ts-jest',
+  },
+  testTimeout: 300000,
+};