PR-733704: fix TypeScript errors in Cypress webpack build

Add tsconfig.cy.json that extends the main tsconfig but removes the
rootDir restriction and adds Cypress types. Point ts-loader in
webpack.cy.config.ts to this dedicated tsconfig, fixing:
- TS6059: cypress/support files outside rootDir src/components
- TS2307: missing @storybook/react-webpack5 type declarations
- TS2339: toBeInTheDocument not found (jest-dom types scope)

webpack.cy.config.ts

@@ -50,7 +50,7 @@ export default {
 				exclude: /node_modules/,
 				use: {
 				loader: 'ts-loader',
-				options: { transpileOnly: true },
+				options: { configFile: 'tsconfig.cy.json' },
 			},
 		  },
 		  {