Export a chat log from the AI panel's chat list. Hovering a chat row now
reveals a download button beside rename/delete; it opens a small menu offering
JSON (full) or Markdown. JSON is lossless — it keeps every per-message
field including the dev diagnostics (ms, scanned cards, actionCount) —
while Markdown is the same transcript in a human-skimmable form with a dim
diagnostics line per assistant turn. The active chat exports its freshest
in-memory thread; other chats export from the device cache. New serializers
(chatToJSON, chatToMarkdown, downloadChat) live in
lib/ai/conversations.ts.
