test(player): pin the phone transport, and the desktop bar not moving

Ten tests, five of which fail on the build before this. The desktop
guard is meant to pass there -- that is its job, and it is the one that
caught a three-pixel regression nothing else could see.

`openTheQueue` moves to the fixtures, because hiding one button failed
ten tests in four files about the back stack and about layout: every
one of them opened the queue by clicking `#queue-button`, and so was
quietly asserting *which* route exists as well as what the queue does.
The route differs by width now and that is the feature.

Two smaller things. The play button is named for its action, so an
exact 'Play' waits out a fixture track -- 11.1s per test, passing by
luck, and it would have failed outright against LONG_TRACK. And the
"nothing playing" case clears the queue itself rather than trusting the
app not to have played anything: `make e2e` runs one long-lived app
across every spec (#168), which is how a deterministic bug first showed
up as a flake.

e2e/specs/queue-overlay.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from '../support/fixtures.js';
+import { test, expect, openTheQueue } from '../support/fixtures.js';
 
 /**
  * #24 — the queue panel does not take the page's width away from it.
@@ -54,15 +54,15 @@ const shellGeometry = (page: import('@playwright/test').Page) =>
     };
   });
 
-async function openQueue(page: import('@playwright/test').Page) {
-  const toggle = page.locator('#queue-button');
-
-  if ((await toggle.getAttribute('aria-expanded')) !== 'true') {
-    await toggle.click();
-  }
-
-  await expect(toggle).toHaveAttribute('aria-expanded', 'true');
-}
+/**
+ * Opening the queue is `openTheQueue`, which takes the route this
+ * viewport offers. It used to be a local helper that clicked
+ * `#queue-button` unconditionally, and #59 hid that button below
+ * 600px -- so the two phone bands here failed on a build where the
+ * queue was working perfectly, having been asserting *how* it opens as
+ * much as what it does.
+ */
+const openQueue = openTheQueue;
 
 test.describe('an open queue leaves the content its width', () => {
   for (const band of BANDS) {