feat(core): added LiveSelectionController

[nikkimk]

Description

• Proof-of-concept for a controller to handle single or multi-selection for components that own their own selection.
• Documentation with demos and code snippets for implementing the controller.
• Refactor of 2nd-gen swc-accordion to leverage focus group navigation and selection controllers.

Motivation and context

This controller could handle selection for accordions, menus, and pickers.

Related issue(s)

• partially fixes SWC-2098, along with PR feat(core): added SelectionController #6487

Screenshots (if appropriate)

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Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

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Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

• Live selection controller

  1. Go to Live selection controller
  2. Verify that the examples work.
  3. Verify that the documentation is sufficient and the examples work as they should.
  4. Verify that automated tests pass.
  5. Verify the examples pass manual keyboard and screenreader testing.

• Accordion

  1. Go to Accordion documentation
  2. Verify that the examples work.
  3. Verify that the public API has not changed.
  4. Verify no visual regressions.
  5. Verify that automated tests pass.
  6. Verify the examples pass manual keyboard and screenreader testing.

• Is the creation and implementation of this controller useful for tabs, accordions, radio groups, swatch groups with selectable swatches, button groups that function as radio groups, menus, and pickers? Or is it easier just to let each custom element handle its own selection management?

Device review

• Did it pass in Desktop?
• Did it pass in (emulated) Mobile?
• Did it pass in (emulated) iPad?

[changeset-bot]

🦋 Changeset detected

Latest commit: 4db4b00

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

This PR includes changesets to release 1 package

Name	Type
@adobe/spectrum-wc	Minor

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Click here if you're a maintainer who wants to add another changeset to this PR

[coveralls]

Coverage Report for CI Build 28976699391

Coverage remained the same at 96.257%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	39169
Covered Lines:	37903
Line Coverage:	96.77%
Relevant Branches:	6460
Covered Branches:	6018
Branch Coverage:	93.16%
Branches in Coverage %:	Yes
Coverage Strength:	461.13 hits per line

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💛 - Coveralls

[github-actions]

📚 Branch Preview Links

• Storybook (Gen2, dev mode)
• Storybook (Gen2, prod mode)
• Documentation Site (Gen1)
• Storybook (Gen1)

🔍 Gen1 Visual Regression Test Results

When a visual regression test fails (or has previously failed while working on this branch), its results can be found in the following URLs:

• Spectrum | Light | Medium | LTR
• Spectrum | Dark | Large | RTL
• Express | Light | Medium | LTR
• Express | Dark | Large | RTL
• Spectrum-two | Light | Medium | LTR
• Spectrum-two | Dark | Large | RTL
• High Contrast Mode | Medium | LTR

Deployed to Azure Blob Storage: pr-6486

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If the changes are unexpected, you can investigate the cause of the differences and update the code accordingly.