Feature request: show per-message timestamps in the terminal conversation UI

Problem

There's currently no way to see when each message in a conversation was sent. In long sessions — especially ones with gaps where I step away and come back — I can't tell how long ago I asked something without manually parsing the session JSONL transcript. The transcript already stores a per-message timestamp, so the data exists; it just isn't surfaced in the UI.

Request

Add an option to display per-message timestamps in the terminal conversation view — ideally a settings.json toggle (e.g. "messageTimestamps": true) and/or a /config option. A relative format ("4h ago") or absolute clock time would both work.

Why it matters

Most chat interfaces (Slack, Discord, web Claude) show this by default. For long-running engineering sessions it's important context for tracking how stale a request or a CI check is.

Workaround today

The only way to recover timing is reading the raw ~/.claude/projects/<project>/<session>.jsonl, which is internal/undocumented and fragile across releases.