test(terminal): add renderer bench smoke script

README.md

@@ -15,3 +15,22 @@ Then open:
 - `http://127.0.0.1:3100/rustui/deep/nested`
 
 Change `app_config/src/lib.rs` to test another base path.
+
+## Terminal Renderer Bench
+
+The terminal benchmark script connects to an already-running dev server; it does
+not start or stop services.
+
+Install the Node dependency and Chromium browser once before running it:
+
+```bash
+npm install
+npx playwright install chromium
+```
+
+```bash
+npm run terminal:bench -- --url http://127.0.0.1:3100/rustui/terminal
+```
+
+It writes `target/terminal-bench/terminal-bench.json` plus screenshots when
+Playwright is available in the workspace.