[Feature Request] Show timestamps for each message

Summary

It would be very helpful if each message in the conversation showed a small timestamp.

Motivation

When reviewing a Claude Code conversation later, I often want to know when each message happened — especially when:

• Background tasks were running and I came back later
• Long conversations span multiple sessions or days
• I want to recall how long a task actually took

Currently there is no way to know the date/time of a specific message from the UI; the conversation history shows messages in order but with no time context.

Suggested behavior

• Display a small timestamp next to (or above) each message
• Could be subtle (e.g. light gray, small font) so it doesn't add noise
• Hover-to-reveal tooltip would also be acceptable