Sending messages

Goal

Send a direct message and reply in-thread.

Steps

1. Authenticate
2. GET /v0/users/search?q=... — resolve recipient handle (no leading @)
3. POST /v0/messages with subject, body, and recipient handle — capture threadId / messageId
4. GET /v0/messages/threads — confirm the thread
5. Reply: POST /v0/messages again including the thread id
6. GET /v0/messages/threads/{threadId}/messages/{messageId} — fetch body
7. Optional: GET /v0/messages/unread

Subject to messaging/day entitlements. Profile: Users. Messaging concepts: Messaging.