Trap keyboard focus within published search

[jpreynat]

What changed

• Keep keyboard focus inside desktop published search while its results are open, wrapping from the final visible popup control back to the search input and in the other direction with Shift+Tab.
• Track the asynchronously mounted portaled popup so the input and results behave as one focus region even though they live in separate DOM trees.
• Leave mobile unchanged because its side sheet already traps focus.

This fixes RND-12430. It adds no dependency; the added production source is about 835 bytes gzip before minification as a conservative upper bound.

Testing

• Added a Playwright regression covering both Tab boundaries against the live local preview: 1 passed.
• bun run typecheck: 27/27 tasks passed.
• Focused lint, formatting, and git diff --check: passed.

A patch changeset is included.

[linear-code]

RND-12430

[changeset-bot]

🦋 Changeset detected

Latest commit: 7f5cb9e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
gitbook	Patch

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[github-actions]

Summary of the deployments:

Version	URL	Status
Vercel	https://gitbook-v2-8gjdeq0x7-gitbook.vercel.app	✅
Cloudflare	https://9680f8ee-gitbook-open-v2-preview.gitbook.workers.dev	✅

Test content

Site	2v	2c
GitBook	https://gitbook-v2-8gjdeq0x7-gitbook.vercel.app/url/gitbook.com/docs	https://9680f8ee-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.com/docs
E2E	https://gitbook-v2-8gjdeq0x7-gitbook.vercel.app/url/gitbook.gitbook.io/test-gitbook-open	https://9680f8ee-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.gitbook.io/test-gitbook-open

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Build	Status	Details	Updated (UTC)
customers-v2-cloudflare (Inspect)	⚠️ Changes detected (Review)	2 changed, 2 ignored	Aug 31, 2026, 10:36 PM
customers-v2-vercel (Inspect)	⚠️ Changes detected (Review)	1 changed, 5 ignored	Aug 31, 2026, 10:34 PM
v2-cloudflare (Inspect)	✅ No changes detected	1 ignored	Aug 31, 2026, 10:38 PM
v2-vercel (Inspect)	✅ No changes detected	8 ignored	Aug 31, 2026, 10:37 PM

[github-actions]

Style invalidation on a large API reference

Elements restyled by opening one popup on the Snyk API reference. A share near or above 100% means the insertion restyles the whole document.

interaction	restyled	page	share	budget
openapi-select	6	10,730	0.1%	25%	✅
search	631	10,730	5.9%	125%	✅