Snapshot taken 2026-07-21. Notable shape change: ReplyParameters.MessageID
becomes optional (*int64) because Bot API 10.2 allows a reply to target
ephemeral_message_id instead. This breaks callers that set MessageID by value,
so examples/echo passes the address now.
New surface includes the ephemeral message methods, sendRichMessage with
InputRichMessageMedia, and the Community service messages.