fix: dispose track publication handles on participant disconnect

[LautaroPetaccio]

Why

When the room processes a participantDisconnected event, it deletes the participant from the remoteParticipants map and emits an event — but never touches the participant's trackPublications. Each TrackPublication wraps an FfiHandle that maps to a native resource. Dropping the JS reference without calling dispose() means the native side never frees the handle. With N participants each publishing M tracks, every disconnect leaks N×M handles.

How

In the participantDisconnected event handler, before emitting the event, loop through participant.trackPublications, call ffiHandle.dispose() on each publication, and clear the map.

Test coverage

• cleans up track publications when a remote participant disconnects — publishes a track, disconnects the publisher, asserts trackPublications is empty on the observer side
• cleans up resources when multiple participants disconnect simultaneously — 4 participants each with a track, all disconnect at once

[changeset-bot]

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Latest commit: b1cd48c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@livekit/rtc-node	Patch

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