Add sticky callout bar for DAGs and Task Instances needing review

### Description

When a DAG run or task instance is paused for human review, users don’t realize they need to take action unless they dig into tabs. We should add a visible sticky callout bar in the header to surface this.

### Use case/motivation

**DAG Overview and DAG Run View:**
- Add a sticky callout bar below the header when any open reviews exist
- The text could be: "Pause for human review. This run is waiting on input"
- We should have a button that says "Review Now". This would open the "Needs Review" list / modal
- If > 1 open review, We can open a list with an accordion (expand per task)

**Task Instance View**
- Show the same callout in the header if the task instance has a pending review
- The text could be: "This task is awaiting human review"
- The "Review now" button should open a modal directly for that task

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

The issue does not name files or tests. Start by tracing the DAG Overview, DAG Run View, and Task Instance View entry points and how the Needs Review list or modal is opened; done means pending reviews show the appropriate sticky callout, and each Review Now action opens the specified list or task modal.

Written by the indexing model from the issue text.