Fix issues in the duplicate item clarification workflow

[sanpohi]

This PR addresses the following issues when clarifying duplicate items from the queue:

• The heading retains the original title instead of updating to the new one provided by the user
• The queue is removed from display after org-gtd-clarify-setup-windows due to delete-other-windows
• The duplicate items share the same ID as the original, which can cause conflicts when referenced by projects
• The buffer name does not use org-gtd-id-get-create, which can cause confusion
• During clarification, the current item is popped from the queue, and only the remaining items can be saved if the user cancels the clarification
• The WIP buffer prefix Org-GTD Clarify is inconsistent with other temporary buffers that use Org GTD ...

Note that the logic of org-gtd-clarify-item can be reused if we persist the item to inbox.org immediately after popping it from the queue. This allows the generation of an Org GTD ID, consistent with the standard clarification process where the Org GTD ID remains in the inbox unless organized. This also prevents the data loss when canceling the clarification.

[Trevoke]

Ah this is great, thank you. Is it too much to ask you to also add tests? If you don't know how to do that, that's fine, just let me know.

[sanpohi]

Thanks for the feedback. I also think adding tests would be helpful. While working on this PR, I noticed the current tests missed checking the :content update.

I was able to set up the Docker images for running tests locally. The e-unit.el API feels very intuitive to me since I've used JUnit before. Let me see if I can add tests to cover my changes.