**Add playlist metadata support to queue and events**

Enhanced queueing functionality to include playlist metadata, such as name, identifier, and track count. Updated event payloads to handle playlist information and introduced a new `playlist_added` event for streamlined notifications. Adjusted tests and documentation to reflect these changes.

docs/events.md

@@ -98,13 +98,13 @@ Key points:
 
 | Type | Payload |
 |---|---|
-| `QUEUE_UPDATED` | `size` (int), `change` (`added`/`removed`/`moved`/`cleared`/`shuffled`), `items` (list). Each item has `index` (0-based position, before the mutation for removals), `identifier`, `title`, `uri`, `requesterId`. `moved` items also carry `fromIndex` and `toIndex`. `cleared` and `shuffled` have an empty `items` (reload the queue on `shuffled`). |
+| `QUEUE_UPDATED` | `size` (int), `change` (`added`/`playlist_added`/`removed`/`moved`/`cleared`/`shuffled`), `items` (list). Each item has `index` (0-based position, before the mutation for removals), `identifier`, `title`, `author`, `duration_ms`, `uri`, `artwork_url`, `requester_id` and `playlist` (`{name, identifier, track_count}` or `null` when the track was not queued from a playlist). `moved` items also carry `fromIndex` and `toIndex`. `cleared` and `shuffled` have an empty `items` (reload the queue on `shuffled`). `playlist_added` is emitted once per playlist load (instead of one `added` event per track), lists only the tracks actually added (duplicates are skipped) and carries a top-level `playlist` object (`name`, `identifier`, `track_count`, the number actually added). |
 | `QUEUE_SHUFFLED` | `size` |
 | `TRACK_ERROR` | `track` (`identifier`, `title`, `author`, `length`, `uri`, `artworkUrl`), `message`, `severity` |
 | `TRACK_STUCK` | `track` (same fields as above), `thresholdMs` |
 | `PLAYER_POSITION` | `position` (ms), `timestamp` (node time, epoch ms), `connected`, `ping` (ms). Sent from Lavalink `PlayerUpdateEvent`, at most once every 5 seconds per guild and only while a track is playing. |
 
-`size` in `QUEUE_UPDATED` is unchanged, so existing consumers keep working.
+Consumers must handle the `playlist_added` change value and the per-item `playlist` field. The REST queue listing (`GET /music/{guildId}/queue`) also reports `playlist` on every entry.
 
 ## Extending the event system