DataViews: Add insert left/right in table column header

[ntsekouras]

What?

Resolves: #72844

This PR adds two menu items in table layout that enables users to insert left or right one of the hidden fields.

Notes

1. I've updated the icons per the mock up here and that this PR doesn't implement any right-click implementation, as it might not be necessary.
2. For reviews hide the whitespace.

Testing Instructions

1. Either in site editor or storybook, in a table DataViews click the column header and play around with the new menu items (insert left / insert right)
2. Observe that everything works as expected.

Screenshots or screencast

[jameskoster]

The multiple arrow icons look a little clunky. I wonder if we should omit the icons for the 'Insert' actions. What do you think @WordPress/gutenberg-design ?

[github-actions]

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[oandregal]

@ntsekouras there's a CI failure because, since a few months ago, every PR to packages/dataviews needs the corresponding entry in the CHANGELOG.

[ntsekouras]

there's a CI failure because, since a few months ago, every PR to packages/dataviews needs the corresponding entry in the CHANGELOG.

@oandregal, yes I'm aware. I'll do it later since I'm still waiting on the design feedback.

[jameskoster]

If no other design feedback arrives I'd lean towards removing the icons for insert left/right.

[fcoveram]

+1 to removing the icons.

[github-actions]

Flaky tests detected in f0f7678.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/19142008744
📝 Reported issues:

• [Flaky Test] ensures List View global shortcut works properly #51533 in /test/e2e/specs/editor/various/list-view.spec.js

[ntsekouras]

I've rebased and updated the util used. I think it's worth it to try this out even with the context menu on table headers. What do you think @jameskoster @youknowriad? In other case, I'll close the PR.

[jameskoster]

I still think it's a nice power-user feature, but happy to defer to other stronger opinions.

[youknowriad]

No strong opinions for me :)

[oandregal]

I've just noticed one thing: we need to disable insert left/right when there's no field hidden.

Screen.Recording.2025-11-20.at.19.39.08.mov

[ntsekouras]

I've just noticed one thing: we need to disable insert left/right when there's no field hidden.

Good catch. I fixed it.

[oandregal]

Can we make it disabled if there are no fields to add?

There's a difference between a menu item that we should never display (e.g., never display insert left in the primary column, or never display left/right if the consumer has disabled moving) vs. a situational context (it's possible to insert fields, but there's none at the moment).

Going to tag @jameskoster for thoughts, but I'm approving in the meantime. It can be addressed as follow-up, if we want to implement what I suggested.

[jameskoster]

Good question. I don't actually have a strong feeling about this so would welcome input from others.

My instinct is that after inserting the last option it's kind of implied that there's no further action to take, and therefore reasonable to hide rather than disable. On the other side of the coin, in a DataViews instance where all fields are visible by default, would a disabled 'Insert left' action be confusing?