Show wall-clock timestamp on completed turn footer

Problem

The turn footer shows how long a turn took (e.g. "brewed for 1m 47s") but not when it finished. After stepping away — waiting between PR review rounds, CI runs, scheduled jobs, etc. — there's no way to tell whether the last turn ended 2 minutes ago or 2 hours ago without re-running something or checking another clock.

A custom status line can show the current time, but that doesn't help: by the time I'm looking, I want to know when the previous turn ended, not what time it is now.

Request

Add a wall-clock timestamp to the completed turn footer alongside the duration. For example:

brewed for 1m 47s · finished 14:32 (12 min ago)

Either an absolute time, a relative "X ago", or both would solve this.

Use case

Waiting between async events — PR review rounds, long CI builds, scheduled agents — where I come back to the terminal and want to gauge how stale the last response is before deciding whether to poke it again.