Codex Desktop leaves headless Playwright/Chrome workers running after session close, causing macOS replayd to stay at ~150% CPU #28352

/Applications/Codex.app/Contents/Resources/cua_node/bin/node --experimental-vm-modules ... --session-id ... --working-dir /Users/saurabh/Documents/GitHub/bioq-one-app

### What steps can reproduce the bug?

I do not yet have a minimal deterministic reproduction, but this is the sequence that produced the issue:

1. Start Codex Desktop on macOS.
2. Run one or more Codex sessions that use visual/browser/computer-use behavior, such as visual audit, screenshots, browser inspection, or local app testing.
3. Close or stop those Codex sessions from the UI.
4. Observe macOS Activity Monitor or run:
   ```bash
   ps -axo pid,ppid,pcpu,pmem,stat,comm,args | sort -k3 -nr | head -25
   ps -axo pid,ppid,pcpu,pmem,stat,comm,args | grep -i 'replayd\|playwright\|headless\|Codex'

In the failing state, replayd remains at ~150-160% CPU and hidden Playwright/headless Chrome workers remain alive under a Codex node process.
Kill the stale Codex worker and observe replayd return to idle:kill <codex-node-worker-pid> <headless-chrome-child-pids>
# if the parent remains:
kill -9 <codex-node-worker-pid>

In my case, the stale processes were:
Codex node worker: 23090
Headless Chrome children: 23091, 23601
After killing those, replayd dropped from ~156% CPU to 0.0% and stayed idle.

### What is the expected behavior?


**Expected behavior**
```md
When a Codex visual/browser/computer-use session stops, closes, errors, or is no longer visible in the UI, Codex should terminate all related Playwright/headless Chrome workers and release any screen-capture resources.

macOS `replayd` should return to idle automatically without requiring the user to manually find and kill hidden Codex worker processes.

### Additional information

Environment:
- Codex App: 26.609.41114 (3888)
- macOS: 14.4.1 (23E224)
- Platform: `23.4.0 arm64 arm`
- Hardware: Apple Silicon MacBook Air, 8 GB RAM

Important control test:
I initially suspected Wispr Flow because it also has audio/video capture helper processes. However, after killing the stale Codex Playwright workers, I opened Wispr Flow and left it idle. `replayd` remained at `0.0%`. This suggests Wispr was not the stuck cause.

The strong evidence is:
- Before killing stale Codex workers: `replayd` ~150-160% CPU.
- After killing stale Codex Playwright/headless Chrome workers: `replayd` immediately dropped to `0.0%`.
- No macOS thermal warning was recorded, but battery drain and device heat were significant.

Suggested fix:
Codex should track all child Playwright/Chromium processes spawned by visual/browser/computer-use sessions and reliably clean them up when the session ends. It would also help to expose a UI command such as "Stop all browser/computer-use workers" or automatically reap orphaned Playwright workers after a timeout.