fix(chess): global Esc handler + stable test selectors for layouts e2e

- LayoutEditor: move Esc handling to a window keydown listener so
  the modal closes regardless of where focus currently sits (the
  prior onKeyDown on the modal div only fired when the root div
  itself held focus).
- LayoutPicker: add data-testid on the description <p> so e2e
  assertions can target it unambiguously instead of relying on
  free-text matches that also select the hidden <option> labels.
- e2e: use the new testid.

All 12 layouts e2e tests pass; existing multiplayer + full-flow
e2e suites still green.

packages/chess/e2e/layouts.spec.ts

@@ -52,7 +52,9 @@ test.describe('LayoutPicker (lobby)', () => {
   test('selecting Dunsany updates the description', async ({ page }) => {
     const picker = page.getByTestId('layout-picker');
     await picker.selectOption('dunsany');
-    await expect(page.locator('text=/Dunsany/i').first()).toBeVisible();
+    await expect(
+      page.getByTestId('layout-picker-description'),
+    ).toContainText(/pawn tide/i);
   });
 
   test('?layoutId=dunsany query param pre-selects the layout', async ({ page }) => {