Ask Chat Ai

Answers a question, optionally posting it straight into the conversation's own thread (postToConversation: true) — that's the @align <question> in-composer command (MessageComposer.tsx), as opposed to the private, answer-returned-only usage ChatAIDialog.tsx has always used and keeps using unchanged. A posted answer is kind="ai" (0020_chat_message_kind.sql) — the ONLY place in this router allowed to write that kind, so a client can never spoof one via the normal POST /messages route.