Show an automatic progress percentage for every running task

Problem

Long-running Codex tasks can take hours or days, but users often have no stable, glanceable indication of overall completion. They have to repeatedly ask for status, and transient activity messages do not answer how close the task is to the requested end goal.

This is especially confusing when a task contains several phases (for example generation, QA, integration, and final validation) or when Codex continues working in the background.

Requested behavior

Show an automatic progress percentage for every running task in the Codex app.

• Display the percentage prominently in the task list/sidebar and inside the task.
• Update it automatically as verified work completes.
• Base it on the whole user goal, including remaining validation and installation work, rather than only the current sub-step.
• Keep the displayed value stable and monotonic unless the scope explicitly changes.
• Optionally expose the completed/total unit count and current phase behind the percentage.
• Clearly distinguish measured progress from an estimate when exact units are unavailable.

Why this helps

A persistent progress indicator would make long-running tasks easier to trust and monitor, reduce repetitive status questions, and let users decide when to return without interrupting the agent.