[BRAPI]: add storage state example for playwright

Author: ruifigueira

src/content/docs/browser-rendering/platform/playwright.mdx

@@ -181,6 +181,33 @@ export default {
 };
 ```
 
+### Storage state
+
+Playwright supports [storage state](https://playwright.dev/docs/api/class-browsercontext#browsercontext-storage-state) to obtain and persist cookies and other storage data.
+
+Here's an example that uses storage state to persist cookies and other storage data in [KV](https://developers.cloudflare.com/kv):
+
+```ts
+// gets persisted storage state from KV or undefined if it doesn't exist
+const storageStateJson = await env.KV_STORAGE_STATE.get('storageState');
+const storageState = storageStateJson ? await JSON.parse(storageStateJson) as BrowserContextOptions['storageState'] : undefined;
+
+await using browser = await launch(env.MYBROWSER);
+// creates a new context with storage state persisted in KV
+await using context = await browser.newContext({ storageState });
+
+await using page = await context.newPage();
+await page.goto(`${url.origin}/increment`);
+
+// do some actions on the page that may update client-side storage
+
+// gets updated storage state: cookies, localStorage and IndexedDB
+const updatedStorageState = await context.storageState({ indexedDB: true });
+
+// persist updated storage state in KV
+await env.KV_STORAGE_STATE.put('storageState', JSON.stringify(updatedStorageState));
+```
+
 ### Keep Alive
 
 If users omit the `browser.close()` statement, the browser instance will stay open, ready to be connected to again and [re-used](/browser-rendering/workers-bindings/reuse-sessions/) but it will, by default, close automatically after 1 minute of inactivity. Users can optionally extend this idle time up to 10 minutes, by using the `keep_alive` option, set in milliseconds: