ChannelListEventHandler

Channel list event listener handler

Registers all event listeners that trigger channel list refresh, and notifies the ViewModel via DataKey.

Monitored event types:

• Channel events (draft, clear, unread, delete, status changes)
• Message events (send, download, delete, recall, refresh, insert, clear)
• Message reception (distinguishes online/offline batch mode)
• Message recall
• Cancel send
• Channel status changes