chore(progress-bar): added migration guide

[miwha-adobe]

Description

Adds a consumer-facing migration guide for Progress Bar, documenting how application developers upgrade from Spectrum 1 <sp-progress-bar> to Spectrum 2 <swc-progress-bar>. The guide is a single new MDX page rendered in Storybook at Progress Bar/Migration guide.

Related issue(s)

• fixes SWC-1779

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

• Migration guide renders and reads correctly in Storybook

  1. Run Storybook for the 2nd-gen workspace and open Progress Bar / Migration guide
  2. Confirm the page renders with no MDX errors and both callouts (the amber breaking-change note and the red "do not target internals" note) display
  3. Expect all in-page anchor links (e.g. "see step 3", "see step 5", "see Styling") to jump to the correct sections

• Code and API references match the migrated component

  1. Cross-check the "What changed", "Added", and "Removed" tables against <swc-progress-bar> (2nd-gen/packages/swc/components/progress-bar/)
  2. Confirm every documented attribute, slot, and --swc-linear-progress-* custom property exists on the component
  3. Expect no stale or hallucinated API (e.g. value, label-position, static-color, accessible-label, value-label, description slot)

Device review

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

Accessibility testing checklist

• Keyboard (required) — The migration guide is a static documentation page with no interactive parts of its own beyond standard in-page anchor links.

  1. Open Progress Bar / Migration guide in Storybook
  2. Tab through the page and activate the in-page anchor links with Enter
  3. Expect focus order to be logical, the focus indicator to be visible, and each link to move focus to the correct section; no focus traps

• Screen reader (required) — Verify document structure and that the documented a11y guidance is correct.

  1. Navigate the page with a screen reader (VoiceOver / NVDA) using heading navigation
  2. Confirm headings are announced in a correct, non-skipping hierarchy and the tables are announced as tables with readable cells
  3. Confirm the guide's a11y instructions are accurate: name is provided via the label slot or accessible-label, indeterminate bars use accessible-label, and role="progressbar" / aria-value* are set internally (not on the host)

[changeset-bot]

⚠️ No Changeset found

Latest commit: f09a54e

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.

This PR includes no changesets

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[github-actions]

📚 Branch Preview Links

• Documentation Site (first-gen)
• Storybook (first-gen)
• Storybook (second-gen)

🔍 First Generation 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-6485

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.