feat(tabs): focusgroup navigation controller refactor

[nikkimk]

Description

Refactor of 2nd-gen swc-tabs to leverage live focusgroup navigation controller.

Motivation and context

Centralizing roving tabindex/arrow key navigation into a single controller for the components that use it.

Related issue(s)

• along with PRs feat(core): added SelectionController #6487 and feat(core): added LiveSelectionController #6486, resolves SWC-2098

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

• Descriptive Test Statement

  1. Go here
  2. Do this action
  3. Expect this result

• Descriptive Test Statement

  1. Go here
  2. Do this action
  3. Expect this result

Device review

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

Accessibility testing checklist

Required: Complete each applicable item and document your testing steps (replace the placeholders with your component-specific instructions).

• Keyboard (required — document steps below) — What to test for: Focus order is logical; Tab reaches the component and all interactive descendants; Enter/Space activate where appropriate; arrow keys work for tabs, menus, sliders, etc.; no focus traps; Escape dismisses when applicable; focus indicator is visible.

  1. Go here
  2. Do this action
  3. Expect this result

• Screen reader (required — document steps below) — What to test for: Role and name are announced correctly; state changes (e.g. expanded, selected) are announced; labels and relationships are clear; no unnecessary or duplicate announcements.

  1. Go here
  2. Do this action
  3. Expect this result

[changeset-bot]

⚠️ No Changeset found

Latest commit: a4fff2e

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[coveralls]

Coverage Report for CI Build 29098714932

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:	461.6 hits per line

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💛 - Coveralls

[github-actions]

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🔍 Gen1 Visual Regression Test Results

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Deployed to Azure Blob Storage: pr-6493

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