fix(clients): Waiting rows say what the task waits on#66

What Changed

Carries pingdotgg/t3code#16213 by @saphid. A waiting thread's row now names the work that will wake the agent, such as "Waiting on 2 subagents" or "Waiting on Review src/math.ts", on web with a matching icon and on mobile in the time label's slot and its VoiceOver label. Commands the agent left running without waiting on them are not named.

On the fork, the named mobile label takes precedence over the bare "Waiting" label from contrib/ctm/mobile-waiting-state, which remains the fallback when nothing is named.

Why

A bare "Waiting" did not say whether the task was about to wake or would sit for a long time. Drop this layer at the refresh after #16213 merges upstream.

UI Changes

Before and after web and iOS screenshots are on pingdotgg/t3code#16213.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes