Record the dashboard, and make the page capturable

node scripts/record-dashboard.mjs drives the gateway with real requests and
screenshots the real dashboard between them with headless Chrome. Screen
recording was the obvious route and the wrong one: it would photograph whatever
else happened to be on screen and needs a permission grant. Headless captures
only the page, needs no permission, and writes frames straight to disk.

The dashboard never finished loading under a headless browser, because it holds
an SSE connection open and polls on an interval — so ?nolive=1 now renders once
and goes quiet. That also makes the page screenshot-testable in general.

Chrome does not reliably exit after --screenshot, so the recorder waits for the
PNG to appear and stop growing rather than guessing a sleep, and treats profile
cleanup as best-effort since Chrome keeps flushing after SIGKILL.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -10,8 +10,14 @@ has a sixteenth of the context window.
 
 ![Freeway demo](demo/freeway-demo.gif)
 
-*Every frame above is a real request against a live provider — recorded by
-`./scripts/demo.sh`, which you can run yourself.*
+**The dashboard, reacting to that same traffic:**
+
+![Freeway dashboard](demo/freeway-dashboard.gif)
+
+*Both are real. The terminal is `./scripts/demo.sh`; the dashboard is headless
+Chrome screenshotting the actual page via `node scripts/record-dashboard.mjs`,
+between real requests. Watch the token totals, cache hit rate and per-model
+counts climb — nothing is mocked up.*
 
 ```
 your app ──▶ Freeway ──┬──▶ Mistral        1B tokens/month
@@ -404,7 +410,8 @@ gateway flatly refuses to bind one with no keys at all.
 ## Development
 
 ```bash
-./scripts/demo.sh       # scripted walkthrough against your real providers
+./scripts/demo.sh                     # scripted walkthrough against your providers
+node scripts/record-dashboard.mjs     # re-record the dashboard GIF
 npm run build           # tsc --build, must be clean
 npm test                # node:test across all workspaces
 npm run smoke           # every route against mock upstreams — run this after adding a provider