Override AlignmentControl component so it includes the Justify text option

[xavier-lc]

Fixes EDI-13

Proposed changes:

• I've added the Justify text option to the AlignmentControl component with the editor.BlockEdit hook.
• I didn't find a way to actually override the existing core AlignmentControl, so what I'm doing is hiding it with css. The hide selector relies on the aria-label tag, so the PR can't be merged until the added strings are translated, since without them users would see the 2 controls:

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

• Apply this changes to your sandbox together with 195635-ghe-Automattic/wpcom
• Go to /wp-admin/post-new.php
• Type something, and check that you get the option to justify it on the align text options:

• Publish the post, check that the text is properly justified:

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack or WordPress.com Site Helper), and enable the update/alignment-control-so-it-includes-justify-option branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack update/alignment-control-so-it-includes-justify-option

bin/jetpack-downloader test jetpack-mu-wpcom-plugin update/alignment-control-so-it-includes-justify-option

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

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---

Follow this PR Review Process:

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Jetpack plugin:

The Jetpack plugin has different release cadences depending on the platform:

• WordPress.com Simple releases happen as soon as you deploy your changes after merging this PR (PCYsg-Jjm-p2).
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  • Scheduled release: December 2, 2025

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[jp-launch-control]

Code Coverage Summary

Coverage changed in 2 files.

File	Coverage	Δ%	Δ Uncovered
projects/packages/jetpack-mu-wpcom/src/class-jetpack-mu-wpcom.php	0/327 (0.00%)	0.00%	1 ❤️‍🩹
projects/packages/jetpack-mu-wpcom/src/features/wpcom-block-editor/class-jetpack-wpcom-block-editor.php	28/264 (10.61%)	0.04%	-1 💚

1 file is newly checked for coverage.

File	Coverage
projects/packages/jetpack-mu-wpcom/src/features/wpcom-alignment-control/wpcom-alignment-control.php	0/14 (0.00%) 💔

Full summary · PHP report · JS report

_{Coverage check overridden by I don't care about code coverage for this PR Use this label to ignore the check for insufficient code coveage. .}