Animate library tabs, rows, editor track lists, status badges and dropzone

Tabs get a sliding indicator that persists across library routes, grid rows flip and collapse on removal, the selection bar and filters crossfade, album tracks move between lists with a crossfade, processing badges pulse and the dropzone scales while dragging.

web-player/src/lib/components/music/library/ManageTrackList.svelte

@@ -62,6 +62,7 @@
 	columns={COLUMNS}
 	rows={tracks}
 	rowKey={(track) => track.id}
+	stagger
 	rowClass={(track) => (player.currentId === track.id ? 'surface-active' : 'hover:bg-hover')}
 >
 	{#snippet head()}