fix(shared): polyfill test environment with Node globals for stability

Configures Jest to use a custom test environment that patches the JSDOM global scope with `fetch`, `Request`, and `Response` from Node.js.

Since Node.js v18+ provides these fetch-related APIs as stable globals, we can reliably polyfill the test environment to ensure they are always available

Author: bratsos

packages/shared/customJSDOMEnvironment.ts

@@ -0,0 +1,9 @@
+import JSDOMEnvironment from 'jest-environment-jsdom';
+
+export default class CustomJSDOMEnvironment extends JSDOMEnvironment {
+  constructor(...args: ConstructorParameters<typeof JSDOMEnvironment>) {
+    super(...args);
+
+    this.global.Response = Response;
+  }
+}

packages/shared/jest.config.js

@@ -6,7 +6,7 @@ const config = {
   displayName: name.replace('@clerk', ''),
   injectGlobals: true,
 
-  testEnvironment: 'jsdom',
+  testEnvironment: './customJSDOMEnvironment.ts',
   roots: ['<rootDir>/src'],
   setupFiles: ['./jest.setup.ts'],