Selection and navigation list UI enhancements

[mgadewoll]

Important

🚧 This PR is currently only used for testing merged updates that are part of https://github.com/elastic/platform-ux-team/issues/1050. 🚧
ℹ️ Once all individual UI changes are separately reviewed and merged into this feature branch, this PR becomes a merge PR.

Included PRs

• [EuiCheckBox] Add new EuiCheckboxControl component #9401
• [EuiSelectable] UI enhancements #9411
• [EuiListItemLayout] Add internal, shared list item component #9530
• [EuiSelectable] Use EuiListItemLayout for rendered list items #9532
• [EuiComboBox] listbox UI enhancements #9538

Summary

API Changes

component / parent	prop / child	change	description

Screenshots

Before	After
{Before image}	{After image}

Impact Assessment

• 🔴 Breaking changes — What will break? How many usages in Kibana/Cloud UI are impacted?
• 💅 Visual changes — May impact style overrides; could require visual testing. Explain and estimate impact.
• 🧪 Test impact — May break functional or snapshot tests (e.g., HTML structure, class names, default values).
• 🔧 Hard to integrate — If integration is complex, stage commits in Kibana/Cloud UI branches for cherry-picking and link to them below.

Impact level: 🟢 None / 🟢 Low / 🟡 Moderate / 🔴 High

Release Readiness

• Documentation: {link to docs page(s)}
• Figma: {link to Figma or issue}
• Migration guide: {steps or link, for breaking/visual changes or deprecations}
• Adoption plan (new features): {link to issue/doc or outline who will integrate this and where}

QA instructions for reviewer

Checklist before marking Ready for Review

• Filled out all sections above
• QA: Tested light/dark modes, high contrast, mobile, Chrome/Safari/Edge/Firefox, keyboard-only, screen reader
• QA: Tested in CodeSandbox and Kibana
• QA: Tested docs changes
• Tests: Added/updated Jest, Cypress, and VRT
• Changelog: Added changelog entry
• Breaking changes: Added breaking change label (if applicable)

Reviewer checklist

• Approved Impact Assessment — Acceptable to merge given the consumer impact.
• Approved Release Readiness — Docs, Figma, and migration info are sufficient to ship.

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: adfac33
• Documentation website
• Storybook

History

• 💚 Build #3056 succeeded adfac33
• 💚 Build #3024 succeeded 40ad6f3
• 💚 Build #3023 succeeded 40ad6f3
• 💚 Build #3022 succeeded 28b4304
• 💚 Build #3021 succeeded 28b4304

cc @mgadewoll

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: adfac33

History

• 💚 Build #6086 succeeded 40ad6f3
• 💚 Build #6085 succeeded 28b4304

cc @mgadewoll