Consider adding the resize handles to the Post Editor

[annezazu]

What problem does this address?

In chatting with @elmastudio and a few others, the topic came up around adding the resizable view currently available in template part focus mode to the post editor:

Post editor view:

preview.mov

Focus mode view:

snapping.mov

What is your proposed solution?

Bring the focus mode resizable option to the post editor to have a more unified and modern approach. This is not a good term but perhaps there's just one menu item under Preview that brings you to the draggable handle view or perhaps simply clicking "preview" takes you there. Here are a few ideas for fun:

Related to this, would be neat to add snapping too: #47360

[github-actions]

Hi,
This issue has gone 180 days without any activity. This means it is time for a check-in to make sure it is still relevant. If you are still experiencing this issue with the latest versions, you can help the project by responding to confirm the problem and by providing any updated reproduction steps.
Thanks for helping out.

[ktmn]

Yes! I want all editors to have the resize handles, so much more convenient.

Any code snippets to accomplish this?