[FEATURE] Preserve "Waiting" green pill until plan is responded to

What feature would you like to see?

When Codex presents a plan and awaits user confirmation (implement or dismiss), the thread should preserve the "Waiting" green pill indicator in the sidebar until the user explicitly responds.

Currently, the "Waiting" status disappears or is not visually persistent, making it impossible to distinguish threads that still have unresponded plan prompts from threads that are idle or completed. When working with multiple concurrent Codex threads, I have to click into each one individually to check whether a plan is pending my response. This is tedious and breaks the multi-thread workflow.

Desired behavior:

• When Codex generates a plan and is waiting for the user to implement or dismiss, display the green "Waiting" pill on that thread in the sidebar
• Keep it visible until the user takes action (implement or dismiss)
• This lets users scan the sidebar at a glance to identify which threads need attention

Use case: I frequently run multiple Codex threads in parallel. Several of them may finish generating plans at different times. Without a persistent visual indicator, I lose track of which threads are awaiting my input and have to open each one to check.

Additional information

• codex-cli 0.106.0
• macOS, Apple Silicon