Fix Windows fixture path resolution in tests

Co-authored-by: garrytrinder <11563347+garrytrinder@users.noreply.github.com>

Author: Copilot

src/test/helpers.ts

@@ -8,8 +8,8 @@ import { DevProxyInstall } from '../types';
  * avoiding the need to copy them to out/ during build.
  */
 export function getFixturePath(fileName: string): string {
-  // process.cwd() is the workspace root when running tests via VS Code test runner
-  return path.resolve(process.cwd(), 'src', 'test', 'examples', fileName);
+  const workspaceRoot = vscode.workspace.workspaceFolders?.[0]?.uri.fsPath ?? process.cwd();
+  return path.resolve(workspaceRoot, 'src', 'test', 'examples', fileName);
 }
 
 /**