Data.contact holds visitor threads keyed by blake3(session token).
Message bodies are a Markdown subset rendered with a strict MarkdownIt
(html=False): the stored html is always markdown-it output, never
sanitized user markup. pagerite/messages.py owns the store ops, wire
payloads and both socket protocols (visitor frames on /_ws, admin frames
on /_api/ws/analytics); the socket wiring follows.