Hidden mobile thread screens still re-render every second for the worktree setup card and the "Working for" label #18922

What happened

On mobile, pushing Files, Review or Terminal over a thread keeps the thread route mounted underneath. worktree-setup-card.tsx runs its own setInterval clock (useSetupClock), used by the setup card and the "Working for" header above it, so the hidden thread screen re-renders once a second until the app goes to the background.

Diagnosis

#15397 gave the working timer and the subagent bar useVisibleSecondClock, which ticks only while the screen is focused and the app is active. These two labels were not moved to it. PR #17701 replaces the local clock with that hook (+5/-19 lines, one file).

Steps to reproduce

1. Open a thread whose worktree setup is running, or that is working.
2. Push Files, Review or Terminal over it.
3. Leave the app in the foreground; the hidden thread screen keeps re-rendering each second.

Version

0.0.44

Environment

apps/mobile, read from source on main; not run on a device or simulator.

Evidence

Visible in the source (`useSetupClock`, `worktree-setup-card.tsx`). Not measured on a device. #15397 reported 60 renders per minute down to 0 for the two timers it covered; that is not a result for these two labels.

Related issues

#15397, #18160 (this report as first filed with the CLI)

Fix applied or workaround

PR #17701 is open. A one-file change to an existing hook.

Filed by

claude (sonnet-5.5) via t3 triage