Add discrepancy handling to A11yPanel

Closes #

What I did

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

[ ] stories
[ ] unit tests
[ ] integration tests
[ ] end-to-end tests

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

[ ] Add or update documentation reflecting your changes
[ ] If you are deprecating/removing a feature, make sure to update MIGRATION.MD

Checklist for Maintainers

[ ] When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts
[ ] Make sure this PR contains one of the labels below:

Available labels
- `bug`: Internal changes that fixes incorrect behavior. - `maintenance`: User-facing maintenance tasks. - `dependencies`: Upgrading (sometimes downgrading) dependencies. - `build`: Internal-facing build tooling & test updates. Will not show up in release changelog. - `cleanup`: Minor cleanup style change. Will not show up in release changelog. - `documentation`: Documentation **only** changes. Will not show up in release changelog. - `feature request`: Introducing a new feature. - `BREAKING CHANGE`: Changes that break compatibility in some way with current major version. - `other`: Changes that don't fit in the above categories.

🦋 Canary release

This pull request has been released as version 0.0.0-pr-29661-sha-2eebee12. Try it out in a new sandbox by running npx storybook@0.0.0-pr-29661-sha-2eebee12 sandbox or in an existing project with npx storybook@0.0.0-pr-29661-sha-2eebee12 upgrade.

More information

| | | | --- | --- | | **Published version** | [`0.0.0-pr-29661-sha-2eebee12`](https://npmjs.com/package/storybook/v/0.0.0-pr-29661-sha-2eebee12) | | **Triggered by** | @valentinpalkovic | | **Repository** | [storybookjs/storybook](https://github.com/storybookjs/storybook) | | **Branch** | [`valentin/add-a11y-discrepancy-handling`](https://github.com/storybookjs/storybook/tree/valentin/add-a11y-discrepancy-handling) | | **Commit** | [`2eebee12`](https://github.com/storybookjs/storybook/commit/2eebee1264ecfead76a5fd6818f61bad84a2de26) | | **Datetime** | Tue Nov 19 15:05:09 UTC 2024 (`1732028709`) | | **Workflow run** | [11915852041](https://github.com/storybookjs/storybook/actions/runs/11915852041) | To request a new release of this pull request, mention the `@storybookjs/core` team. _core team members can create a new canary release [here](https://github.com/storybookjs/storybook/actions/workflows/canary-release-pr.yml) or locally with `gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=29661`_

Greptile Summary

Added discrepancy handling to the A11YPanel component to detect and display messages when accessibility test results differ between CLI and browser environments.

Added new TestDiscrepancyMessage component in /code/addons/a11y/src/components/TestDiscrepancyMessage.tsx to display environment-specific test result differences
Added discrepancy field to A11yContext in /code/addons/a11y/src/components/A11yContext.tsx to track test result mismatches
Added comprehensive test coverage in /code/addons/a11y/src/components/A11yContext.test.tsx for discrepancy scenarios
Added documentation links in /code/addons/a11y/src/constants.ts for explaining discrepancy cases
Added new stories in /code/addons/a11y/template/stories/TestDiscrepancyMessage.stories.tsx to showcase different discrepancy states

storybookjs / storybook