Subscribes to presence updates for the given chat and returns the current state. Subsequent changes emit presence_update webhook events (if enabled in webhook settings).

Important — subscription model:

• Presence in Web is subscription-based. You MUST call this action at least once per chat you want to track. Without a subscribe, the presence_update webhook never fires for that chat.
• Calling this action again acts as a renewal. Subscriptions are lost on instance reconnect — re-subscribe after any 'ready' event if you want continuous tracking.
• Privacy reciprocity: if the instance account hides its own last-seen in the settings, it cannot read others' last-seen either. Expect deny:true or hasData:false in that case.
• High-frequency event — a single active chat can produce 10+ presence_update webhooks per minute. Debounce on your side.
• Groups: chatstate is always null. Use typingParticipants and recordingParticipants instead. isOnline on a group = 'at least one member online'.

Note: This endpoint is currently in beta and may change without notice.