List Review Chat Turns

List the caller's private review-chat thread on a snapshot (renderer-facing).

Workspace membership gates the call; the thread is scoped to the authenticated reviewer, so one reviewer never sees another's thread and the contributor sees none. Turns come back oldest-first so the Chat tab repaints the conversation on reload and chains the next message onto the last. The agent-facing context GET is the wrong surface here: it needs the review-chat JWT the renderer never holds and rebuilds one focal turn's ancestry, not the whole thread.