Support Plex Webhooks

[arsaboo]

When playing music using Plex, I see the play history get updated. However, Music Assistant creates no webhook that can trigger other services. For example, I am using webhooks in Plex to scrobble to Navidrome:

This works perfectly when playing music directly from Plex but does not work when using Music Assistant, which does not trigger any events in Plex.

[anatosun]

Building on this discussion, it would be valuable if Music Assistant exposed generic webhook endpoints that could accept incoming webhooks from various providers. This would enable truly real-time synchronization.

Use Case:
Currently, Music Assistant periodically polls providers like Plex for updates. With webhook support, these updates could happen in real-time:

• When a playlist is modified in Plex (songs added/removed/reordered)
• When new content is added to Plex libraries
• When metadata is updated in Plex

...the webhook would be triggered immediately, and Music Assistant could reflect these changes instantly rather than waiting for the next polling cycle.