onChannelMessagePosted watches one team channel and emits both root messages
and replies.
Example
automations/watch-teams-channel.automation.ts
Options
Trigger data
ReturnsTeamsChatMessage & { teamId: string; channelId: string }. The message
includes normalized body, ID, sender, timestamps, attachments, mentions,
reactions, importance, optional replyToId, and provider metadata. A
replyToId distinguishes replies from root posts.
Options are static subscription configuration and cannot use runtime signals.