New example along storyline (bonus): New example for Human in the Loop operators

### Description

As described in https://cwiki.apache.org/confluence/display/AIRFLOW/Examples+Refurbish

If HITL implementation is completed, add a Human in the Loop example to the storyline. Storyline is to be extended for this - creativity for a use case is needed.

### Use case/motivation

Airflow Examples have been grown in number and focus over the past years. They purpose multiple things:

Serve as tutorials to learn Airflow DAG implementation
Serve with code snippets for documentation
Serve for testing the setup
(some) service for CI integration testing

Some example DAGs are in a good quality, some are not following best practices. Current examples do not follow a structure.

There are example DAGs contained in the Airflow core (currently pushed to standard provider/example_dags) as well as there are more examples in other providers. But examples from other providers are lot loaded automatically.

So in the [Airflow 3 Dev Calls](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+3+Dev+call%3A+Meeting+Notes#Airflow3Devcall:MeetingNotes-22May2025) there was a demand named to clean-up and optimize example DAGs.

### 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)

Start with the Examples Refurbish plan and review the existing Human in the Loop implementation and storyline examples under standard provider/example_dags. Define a suitable use case and determine where the new example belongs in the storyline. Done means a Human in the Loop example is added and aligned with the intended example structure.

Written by the indexing model from the issue text.