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/detect-node-es/es5/node.d.ts

@@ -0,0 +1,4 @@
+/**
+ * returns true if the current environment is NodeJS
+ */
+export declare const isNode: boolean;