feat(now-playing): plain text instead of links in the phone mini player

The bottom bar's title, artist and "Playing from X" all navigate. In a
bar sized for a bar they are a few characters of text, which is not a
touch target — and explore-link holds its navigation for one
double-click interval and drops it if a second click arrives, a gesture
that exists so double-clicking a row can play it and that means nothing
on touch.

Below the shell's phone breakpoint the three render as plain text. The
words are unchanged: the source line still says where the queue came
from, because dropping the link is the change and dropping the
information would be a different and worse one. The cover art already
carries the phone-only button that opens the full-screen Now Playing
view, which is where the links live.

This is in JS rather than in the stylesheet because what changes is the
content, not its appearance — no CSS rule takes a click handler off an
element. matchMedia is read in connectedCallback for the reason the
reduce-motion query beside it already is, so a test can answer it first.

Two smaller things. PHONE_QUERY moves out of track-list.ts into
utils/breakpoints.ts: it was a private const when one component needed
it, and a second reader is where a copy starts drifting from index.css.
And `phone` joins geometryKey(), because crossing the breakpoint swaps a
link for a bare string and the marquee travels a distance read from
measuring it — the words being identical either side is not the same as
the box measuring the same.

Closes #61

frontend/src/components/track-list/track-list.ts

@@ -11,6 +11,7 @@ import {
 import { SelectionController } from '@utils/selection-controller';
 import type { SelectionHost } from '@utils/selection-controller';
 import { ViewLifecycleMixin } from '@utils/view-lifecycle';
+import { PHONE_QUERY } from '@utils/breakpoints';
 import {
     ContextMenuController,
     contextMenuStyles,
@@ -105,9 +106,6 @@ const ROW_CHROME_WIDTH =
 const ROW_HEIGHT = 33;
 const PHONE_ROW_HEIGHT = 52;
 
-/** The shell's phone breakpoint, as `index.css` and every component
- *  stylesheet spells it. */
-const PHONE_QUERY = '(max-width: 599px)';
 
 // Inline SVG paths for favorite icons — eliminates wa-icon shadow DOM
 // overhead (30-50 shadow roots during scroll).  Font Awesome 6 paths.