Correct the docs: a second driver is refused, and has been for a while

The README told readers nothing stopped two clients driving one device,
and the Playwright config repeated it in a comment. Both predate
inputOwners. The claim is not merely stale but actively misleading:
someone reading it would design around a hazard we already handle, and
would have no warning about the two real consequences — that an open
console tab holds the device against their own test run, and that a
client which dies without closing its socket keeps the claim until the
server restarts.

Author: omnarayan

README.md

@@ -107,7 +107,10 @@ on durable selectors.
   the effect. Tests should prove the app is taking input before relying on it.
 - **Two-finger gestures are dropped on Android.** They work on iOS; there is no mapping for them
   in the Android driver, and they are discarded rather than guessed at.
-- **Nothing refuses a second driver** on the same device yet.
+- **A device serves one driver at a time**, and a second claim is refused rather than shared.
+  That includes the console: a browser tab left open on a device will refuse your test run,
+  and only the refused side is told why. There is no keepalive yet, so a client that dies
+  without closing its socket holds the device until the server restarts.
 - Relaunching an app does not reset its state.
 
 ## Licence

examples/playwright/playwright.config.ts

@@ -6,10 +6,10 @@ import { defineConfig } from '@playwright/test';
 export default defineConfig({
   testDir: './tests',
   // A device serves one driver at a time. Playwright parallelises across
-  // files by default, which points two specs at the same simulator and
-  // has them fight over it — each passes alone and the pair fails
-  // together. DeviceDeck does not yet refuse a second claim, so the
-  // constraint has to be honoured here.
+  // files by default, which points two specs at the same simulator;
+  // DeviceDeck refuses the second claim, so the run fails loudly rather
+  // than interleaving touches into nonsense. Loud is better than silent,
+  // but it still fails — so keep the worker count at one.
   workers: 1,
   fullyParallel: false,
   timeout: 60_000,