fix: resolve ES modules compatibility in E2E test files

- Replace __dirname with import.meta.url pattern for ES modules compatibility
- Add fileURLToPath imports to all E2E test files
- Fix duplicate require statements in setup-verification.spec.ts
- Update playwright.config.ts to use relative path instead of __dirname

This fixes the 'ReferenceError: __dirname is not defined in ES module scope' error
when running Playwright tests in the ES modules environment.

node_modules/react-style-singleton/README.md

@@ -0,0 +1,45 @@
+react-style-singleton
+====
+
+__300b__ with all dependencies, minified and gzipped
+
+
+Creates a style component with internal _tracker_.
+- Adds styles to the browser on the __first__ instance mount.
+- Removes after the __last__ instance unmount.
+- Thus helps you deliver styles you need to the customer, and clean up later.
+- Is not server-side rendering compatible!
+
+
+# API
+
+## Component
+
+```js
+import {styleSingleton} from 'react-style-singleton'
+
+const Style = styleSingleton();
+
+export const App = () => (
+  <Style styles={'body {color:red}'} />
+);
+```
+
+## Hook
+
+```js
+import {styleHookSingleton} from 'react-style-singleton';
+
+const useStyle = styleHookSingleton();
+const useAnotherStyle = styleHookSingleton();
+
+export const App = () => {
+  useStyle('div {color:red}');
+  useAnotherStyle('body { background-color:red }');
+  return (<div />);
+}
+```
+
+# License
+
+MIT