fix: set kind as agent during token creation for beyond presence plugin

[karlsonlee-livekit]

Description

• Explicitly configures the Beyond Presence avatar to join as an agent participant. This resolves an issue where the avatar was defaulting to standard, which prevented proper track separation for recording.

Changes Made

• Set at.kind = 'agent' during AccessToken generation in AvatarSession.start.

Pre-Review Checklist

• Build passes: All builds (lint, typecheck, tests) pass locally
• AI-generated code reviewed: Removed unnecessary comments and ensured code quality
• Changes explained: All changes are properly documented and justified above
• Scope appropriate: All changes relate to the PR title, or explanations provided for why they're included
• Video demo: A small video demo showing changes works as expected and did not break any existing functionality using Agent Playground (if applicable)

Testing

• Automated tests added/updated (if applicable)
• All tests pass
• Make sure both restaurant_agent.ts and realtime_agent.ts work properly (for major changes)

Additional Notes

---

Note to reviewers: Please ensure the pre-review checklist is completed before starting your review.

[changeset-bot]

🦋 Changeset detected

Latest commit: 7dab8db

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

This PR includes changesets to release 16 packages

Name	Type
@livekit/agents-plugin-bey	Patch
@livekit/agents	Patch
@livekit/agents-plugin-anam	Patch
@livekit/agents-plugin-baseten	Patch
@livekit/agents-plugin-cartesia	Patch
@livekit/agents-plugin-deepgram	Patch
@livekit/agents-plugin-elevenlabs	Patch
@livekit/agents-plugin-google	Patch
@livekit/agents-plugin-inworld	Patch
@livekit/agents-plugin-livekit	Patch
@livekit/agents-plugin-neuphonic	Patch
@livekit/agents-plugin-openai	Patch
@livekit/agents-plugin-resemble	Patch
@livekit/agents-plugin-rime	Patch
@livekit/agents-plugin-silero	Patch
@livekit/agents-plugins-test	Patch

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[davidzhao]

lg!