docs: add local demo instructions and a root dev script

CONTRIBUTING.md

@@ -9,14 +9,12 @@
 
 ## Demo Development Server
 
-- `npm start` from `demo` directory will run the component's demo app at [http://localhost:3000](http://localhost:3000) with hot module reloading.
+- `npm run dev` from the `demo` directory runs the demo app at [http://localhost:3000](http://localhost:3000) with hot module reloading. The demo imports the component straight from `src/`, so it doubles as a development harness.
 
 ## Running Tests
 
 - `npm test` will run the tests once.
-
 - `npm run test:coverage` will run the tests and produce a coverage report in `coverage/`.
-
 - `npm run test:watch` will run the tests on every change.
 
 ## Building

README.md

@@ -28,7 +28,13 @@ Use it when you need email template creation inside your app without building an
 
 ## Live Demo
 
-Check out the live demo here: https://react-email-editor-demo.netlify.app/ ([Source Code](https://github.com/unlayer/react-email-editor/tree/master/demo/src))
+Check out the live demo here: https://react-email-editor-demo.netlify.app/ ([Source Code](https://github.com/unlayer/react-email-editor/tree/master/demo/src)), or run it locally — a Vite-based demo lives in [`demo/`](demo):
+
+```sh
+cd demo
+npm install
+npm run
+```
 
 ## Installation
 

package.json

@@ -28,6 +28,7 @@
   },
   "scripts": {
     "start": "tsup --watch",
+    "dev": "npm --prefix demo install && npm --prefix demo run dev",
     "build": "tsup",
     "test": "vitest run",
     "test:legacy": "vitest run --config vitest.legacy.config.ts",