feat(toast): migrate to gen2

[rise-erpelding]

Description

Migrates Toast component to Gen2

Motivation and context

Migrates existing 1st gen (standalone) Toast component to Gen2, and implements a new container to handle multiple toasts. See RSP implementation.

Related issue(s)

• part of epic SWC-2255
• addresses SWC-2262 (review and finalize toast migration)

PR breakdown/checklist

• SWC-2256 A11y analysis docs(toast): accessibility migration analysis #6442
• SWC-2257 Migration plan docs(toast): migration plan #6686
• SWC-2258 Part 1 File structure for standalone toast, container planning chore(toast): setup, closing decisions, container planning #6753
• SWC-2258 Part 2 Standalone toast API/TypeScript/Accessibility feat(toast): standalone api/a11y #6817
• SWC-2259 Toast S2 visual fidelity
• SWC-2567 Implement toast container/queue
• SWC-2260 Review and complete test suites
• SWC-2261 Storybook docs and consumer migration guide
• SWC-2262 Review and finalize migration

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: 69c0541

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

Click here to learn what changesets are, and how to add one.

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

[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-6818

If the changes are expected, update the current_golden_images_cache hash in the circleci config to accept the new images. Instructions are included in that file.
If the changes are unexpected, you can investigate the cause of the differences and update the code accordingly.