feat(web): one track-list row shape, and drag reorder that snaps (M494, #5393)

Every track list (album, Liked, Search, Search → Tracks, playlist,
History) now draws its rows with TrackListRow inside a TrackList box,
in place of four row components that had drifted apart:

- TrackListRow owns the look: lead column, title over "artist · album",
  like, radio, add to queue, menu, duration, then a trailing slot. It
  also owns the stripe, hover, the now-playing band and the
  unavailable state. The stripe is dropped on now-playing and selected
  rows, where Tailwind would otherwise let `odd:` win.
- TrackRow, PlaylistTrackRow and HistoryRow are wrappers that keep only
  their behaviour: track number and multi-select; grip, remove and
  dead-entry states; cover and timestamp. Playlist and History rows
  gain radio, add and the menu, so every list offers the same actions.
- The radio control is Lucide's Radio icon, not the 📻 emoji.
- Enter on a control inside a row now belongs to that control. The old
  TrackRow played the track when Enter was pressed on "add to queue".
- TrackList has no fill, so the stripe shows on playlists too.

Drag reorder (#5393): neodrag kept the drop offset, so after the list
re-rendered the dragged row sat between two slots. reorderDrag, shared
by the playlist and queue rows:
- snaps the row to whole rows while dragging;
- resets it to its slot on drop;
- on playlists, gives the touch gesture to the grip only, so the list
  still scrolls by touch.
The playlist page reorders optimistically and rolls back on error.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/routes/library/liked/liked.test.ts

@@ -21,7 +21,7 @@ vi.mock('#lib/api/likes.js', () => ({
 
 vi.mock('#lib/api/client.js', () => apiClientMock());
 vi.mock('#lib/player/store.svelte.js', () => ({
-  playQueue: vi.fn(), enqueueTrack: vi.fn(), enqueueTracks: vi.fn(),
+  playQueue: vi.fn(), enqueueTrack: vi.fn(), enqueueTracks: vi.fn(), playRadio: vi.fn(),
   player: { current: undefined }
 }));