Fix FormControl + SelectPanel accessible name to address SR issues

[llastflowers]

Addresses https://github.com/github/accessibility-audits/issues/14989

Changelog

Changed

Fixed SR announcement issue for FormControl.Label + SelectPanel where label[for] referenced the SelectPanel’s anchor button, causing the announcement to drop the selected items; we now avoid htmlFor in this case and auto-compose the anchor’s aria-labelledby from the label and selected value.

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github-ui (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: 640a24d

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

This PR includes changesets to release 1 package

Name	Type
@primer/react	Patch

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[github-actions]

⚠️ Action required

👋 Hi, this pull request contains changes to the source code that github/github-ui depends on. If you are GitHub staff, test these changes with github/github-ui using the integration workflow. Or, apply the integration-tests: skipped manually label to skip these checks.

[Copilot]

Pull request overview

This PR fixes an accessible-name regression when FormControl.Label is used with SelectPanel, where wiring the label via htmlFor to the SelectPanel’s anchor button caused screen readers to announce only the label (dropping the selected value). The change introduces FormControl→SelectPanel coordination so the anchor’s accessible name is composed from both the label and the selected value.

Changes:

• Add isReferenced + labelId to FormControl context to control whether FormControl.Label should set htmlFor.
• Update FormControl.Label to optionally omit htmlFor and to default its own id from context.
• Update SelectPanel to auto-compose the anchor’s aria-labelledby from the label id + selected value (and render the selected value in an id’d <span>).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
packages/react/src/SelectPanel/SelectPanel.tsx	Auto-wires anchor aria-labelledby to include FormControl label + selected value.
packages/react/src/FormControl/_FormControlContext.tsx	Extends FormControl context with isReferenced and labelId used for labeling behavior.
packages/react/src/FormControl/FormControlLabel.tsx	Uses context to set a default id and to suppress htmlFor when not appropriate.
packages/react/src/FormControl/FormControl.tsx	Detects SelectPanel input and provides isReferenced/labelId via context.

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/15139

[primer-integration]

Integration test results from github/github-ui:

CI Passed
VRT Passed
Projects Passed

All checks passed!

[TylerJDev]

LGTM!

[llastflowers]

skipping integration tests as they passed but stopped reporting in CI after I added the changeset