Fields: implement `excerpt`

[oandregal]

Part of #76076

What

Implement a new excerpt field that mimics how the post editor inspector works:

Why

We want to implement a DataForm-based editor inspector, see #76076

How

Implement new field in @wordpress/fields.

[im3dabasia]

@oandregal

I implemented this locally and have attached a screencast showing the implementation. However, I’m wondering if this is something that is actually needed in the Quick Edit section or the Site Editor inspector panel.

Pages don’t support excerpts by default, so for this experiment I added post type support for excerpts in order to implement it without making major changes to the DataViews code.

Previously, there was an experiment that allowed posts to be edited in the Site Editor, but I believe that experiment has since been removed.

If this approach looks good, I can go ahead and raise a PR for the work I’ve done.

Screen.Recording.2026-03-11.at.12.43.06.PM.mov

[oandregal]

Thanks for taking a look @im3dabasia. This task is part of this experiment "DataForm in the editor inspector", that can be enabled via Gutenberg > Experiments. The experiment is locked to post & page post types for now, so we can scope work to those and then open it up for others. This field would not be necessary for QuickEdit, which is only supported in the site editor's pages screen, but it'd be for the post editor inspector. Does that help?