Proposal: Display Commit SHA in `gh run watch` output

### Describe the feature or problem you’d like to solve

Currently, when using `gh run watch` to monitor an active workflow, the interface displays the workflow name and status, but it does not show the **Commit SHA** associated with the run being watched.

When multiple workflows are triggered in rapid succession (e.g., during a rebase or multiple hotfixes), it can be difficult to verify at a glance exactly which commit's execution is being monitored in the terminal without cross-referencing other commands or the Web UI.

### Proposed solution

I propose adding the **Commit SHA** (preferably the short 7-character hash) to the output of `gh run watch`.

**Benefits:**
* **Instant Confirmation:** Users can immediately verify they are watching the correct run that corresponds to their latest local `git push`.
* **Reduced Context Switching:** It eliminates the need to check `gh run list` or the GitHub UI just to find the hash of the currently watched run.
* **Better Monitoring Experience:** Provides the necessary Git context for developers who are debugging or waiting for a specific deployment to finish.

### Additional context

I previously submitted a Pull Request (**#12613**) to implement this feature for `gh run watch`. I am opening this issue to discuss the best placement for the SHA in the output to ensure it aligns with the GitHub CLI's existing UX and design standards. I am happy to refine the implementation based on the feedback from the maintainers.