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/lib/components/TrackListRow.svelte

@@ -0,0 +1,151 @@
+<script lang="ts">
+  // The one shape every track list in the web app draws (milestone 494):
+  // a lead column (track number, drag grip or cover), title over a muted
+  // subtitle, then like, radio, add-to-queue, the track menu and the
+  // duration, then whatever the list adds at the end (remove, a timestamp).
+  // The wrappers — TrackRow, PlaylistTrackRow, HistoryRow — own behaviour
+  // (selection, reorder, remove); this component owns how a row looks, so
+  // the lists cannot drift apart again.
+  import type { Snippet } from 'svelte';
+  import { Plus, Radio } from 'lucide-svelte';
+  import type { TrackRef } from '#lib/api/types.js';
+  import { formatDuration } from '#lib/media/duration.js';
+  import { player, enqueueTrack, playRadio } from '#lib/player/store.svelte.js';
+  import LikeButton from './LikeButton.svelte';
+  import TrackMenu from './TrackMenu.svelte';
+  import { reorderDrag, type ReorderDragOptions } from './reorder-drag';
+
+  let {
+    title,
+    subtitle = '',
+    durationSec,
+    track,
+    ariaLabel,
+    rowTitle,
+    isSelected = false,
+    disabled = false,
+    struck = false,
+    drag = null,
+    onActivate,
+    lead,
+    note,
+    trailing
+  }: {
+    title: string;
+    subtitle?: string;
+    durationSec: number;
+    /** The playable track. null when the row cannot be played, which hides
+        like, radio, add and the menu: there is nothing for them to act on. */
+    track: TrackRef | null;
+    ariaLabel: string;
+    /** Tooltip for the whole row. */
+    rowTitle?: string;
+    isSelected?: boolean;
+    disabled?: boolean;
+    /** Strike the title through: the track is gone for good. */
+    struck?: boolean;
+    drag?: ReorderDragOptions | null;
+    onActivate: (e: MouseEvent | KeyboardEvent) => void;
+    lead?: Snippet;
+    /** Appended to the subtitle line, e.g. a "File missing" marker. */
+    note?: Snippet;
+    trailing?: Snippet;
+  } = $props();
+
+  const isCurrent = $derived(!!track && player.current?.id === track.id);
+
+  // The stripe is only drawn on rows with no state of their own. Tailwind
+  // emits `odd:` after the plain utilities, so a striped odd row would win
+  // over the now-playing or selected background.
+  const background = $derived(
+    isCurrent
+      ? 'border-l-2 border-l-accent bg-surface-hover'
+      : isSelected
+        ? 'bg-surface-hover'
+        : 'odd:bg-surface/50 hover:bg-surface-hover'
+  );
+
+  function onclick(e: MouseEvent) {
+    if (!disabled) onActivate(e);
+  }
+
+  function onkeydown(e: KeyboardEvent) {
+    // Keys pressed on a control inside the row belong to that control.
+    if (e.target !== e.currentTarget) return;
+    if (e.key !== 'Enter' && e.key !== ' ') return;
+    e.preventDefault();
+    if (!disabled) onActivate(e);
+  }
+
+  function onRadio(e: MouseEvent) {
+    e.stopPropagation();
+    if (track) playRadio(track.id);
+  }
+
+  function onAdd(e: MouseEvent) {
+    e.stopPropagation();
+    if (track) enqueueTrack(track);
+  }
+</script>
+
+<div
+  role="button"
+  tabindex="0"
+  aria-label={ariaLabel}
+  aria-disabled={disabled || undefined}
+  title={rowTitle}
+  data-selected={isSelected}
+  {onclick}
+  {onkeydown}
+  use:reorderDrag={drag}
+  class="group relative flex w-full items-center gap-3 px-3 py-2 text-left text-sm
+         transition-colors focus-visible:outline-solid focus-visible:outline-2
+         focus-visible:outline-accent [&.neodrag-dragging]:z-10
+         [&.neodrag-dragging]:bg-surface-hover [&.neodrag-dragging]:shadow-lg
+         {background}
+         {disabled ? 'cursor-default text-text-muted' : 'cursor-pointer text-text-primary'}"
+>
+  {#if lead}
+    <span class="flex w-8 shrink-0 items-center justify-center">{@render lead()}</span>
+  {/if}
+
+  <span class="min-w-0 flex-1">
+    <span class="block truncate {struck ? 'line-through' : ''}">{title}</span>
+    {#if subtitle || note}
+      <span class="block truncate text-xs text-text-secondary">
+        {subtitle}{#if note}{@render note()}{/if}
+      </span>
+    {/if}
+  </span>
+
+  {#if track}
+    <LikeButton entityType="track" entityId={track.id} />
+    <button
+      type="button"
+      aria-label="Play radio from this track"
+      title="Play radio"
+      onclick={onRadio}
+      class="hidden shrink-0 rounded p-1 text-text-secondary hover:text-text-primary sm:inline-flex"
+    >
+      <Radio size={16} strokeWidth={1} />
+    </button>
+    <button
+      type="button"
+      aria-label={`Add ${track.title} to queue`}
+      title="Add to queue"
+      onclick={onAdd}
+      class="hidden shrink-0 rounded p-1 text-text-secondary hover:text-text-primary sm:inline-flex"
+    >
+      <Plus size={16} strokeWidth={1} />
+    </button>
+    <TrackMenu {track} />
+  {/if}
+
+  <span class="w-12 shrink-0 text-right text-xs tabular-nums text-text-secondary">
+    {formatDuration(durationSec)}
+  </span>
+
+  {#if trailing}
+    {@render trailing()}
+  {/if}
+</div>