feat(web): TrackRow div+role button with onPlay prop and + queue button

Outer <button> becomes <div role="button" tabindex="0"> with keyboard
handlers (Enter/Space) so a real <button> for + queue can nest without
invalid HTML. New optional onPlay prop overrides the default
playQueue(tracks, index); used by the search Tracks section to call
playRadio(track.id) instead. + queue button calls enqueueTrack and
stops propagation so the row click does not fire.

web/src/lib/components/TrackRow.test.ts

@@ -3,11 +3,12 @@ import { render, screen, fireEvent } from '@testing-library/svelte';
 import type { TrackRef } from '$lib/api/types';
 
 vi.mock('$lib/player/store.svelte', () => ({
-  playQueue: vi.fn()
+  playQueue: vi.fn(),
+  enqueueTrack: vi.fn()
 }));
 
 import TrackRow from './TrackRow.svelte';
-import { playQueue } from '$lib/player/store.svelte';
+import { playQueue, enqueueTrack } from '$lib/player/store.svelte';
 
 const tracks: TrackRef[] = [
   {
@@ -44,7 +45,34 @@ describe('TrackRow', () => {
 
   test('clicking the row calls playQueue(tracks, index)', async () => {
     render(TrackRow, { props: { tracks, index: 1 } });
-    await fireEvent.click(screen.getByRole('button'));
+    await fireEvent.click(screen.getByRole('button', { name: /Freddie Freeloader/ }));
     expect(playQueue).toHaveBeenCalledWith(tracks, 1);
   });
+
+  test('Enter on the row activates play', async () => {
+    render(TrackRow, { props: { tracks, index: 0 } });
+    await fireEvent.keyDown(screen.getByRole('button', { name: /So What/ }), { key: 'Enter' });
+    expect(playQueue).toHaveBeenCalledWith(tracks, 0);
+  });
+
+  test('Space on the row activates play', async () => {
+    render(TrackRow, { props: { tracks, index: 0 } });
+    await fireEvent.keyDown(screen.getByRole('button', { name: /So What/ }), { key: ' ' });
+    expect(playQueue).toHaveBeenCalledWith(tracks, 0);
+  });
+
+  test('onPlay prop overrides default playQueue', async () => {
+    const onPlay = vi.fn();
+    render(TrackRow, { props: { tracks, index: 1, onPlay } });
+    await fireEvent.click(screen.getByRole('button', { name: /Freddie Freeloader/ }));
+    expect(onPlay).toHaveBeenCalledWith(tracks, 1);
+    expect(playQueue).not.toHaveBeenCalled();
+  });
+
+  test('+ queue button calls enqueueTrack and does NOT trigger row play', async () => {
+    render(TrackRow, { props: { tracks, index: 0 } });
+    await fireEvent.click(screen.getByRole('button', { name: /add to queue/i }));
+    expect(enqueueTrack).toHaveBeenCalledWith(tracks[0]);
+    expect(playQueue).not.toHaveBeenCalled();
+  });
 });