**Improve event handling with new music and queue updates**

Added new `MusicEvent` types, including `TRACK_ERROR`, `TRACK_STUCK`, and `PLAYER_POSITION`, providing enhanced diagnostics and feedback. Improved queue mutation notifications by introducing granular events like `added`, `removed`, `moved`, `cleared`, and `shuffled`. Updated tests and documentation to reflect the changes, ensuring consistency and clarity across the event system.

docs/events.md

@@ -91,6 +91,21 @@ Key points:
   `TaskManager.getInstance().handle(context)`.
 - **`null` contexts** (bot messages, consumer-only events) are simply not routed anywhere.
 
+## Webhook music events
+
+`MusicEvent` instances are delivered by `WebhookDispatcher`. Every event carries `type`, `guildId`,
+`timestamp` and `seq`; the payloads of the queue and player events are:
+
+| 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_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.
+
 ## Extending the event system
 
 To handle a new event type: