docs: add consumer migration guides for S2 components

[cdransf]

Description

Adds migration.md files for 7 components in 2nd-gen/packages/swc/components/, following the pattern established
by the avatar migration guide:

• asset — tag/package rename, CSS vars removed (token-based), shadow DOM class changes
• badge — tag/package rename, CSS var rename, new subtle/outline attributes, 5 new color variants
• divider — tag/package rename, CSS var rename, shadow DOM structure change
• icon — tag/package rename, name/src attributes removed, xxs/xxl sizes removed, slot-only SVG
• progress-circle — tag/package rename, CSS var rename, static-color="black" added, SVG rendering change
• status-light — tag/package rename, disabled removed, accent variant removed, 5 new color variants
• typography — class prefix .spectrum-* → .swc-*, light/uppercase/strong-emphasized removed, new Title variant
  and prose container

Each guide includes: installation steps, quick reference table, per-change before/after examples, new features,
and accessibility notes. Follows the same per-component structure proposed in draft #6145.

Motivation and context

Application developers migrating from 1st-gen to 2nd-gen need practical, consumer-focused guidance that goes
beyond internal implementation analysis. These docs cover the day-to-day upgrade path: what to search for, what
to change, and how to validate the result.

Related issue(s)

• SWC-1675
• related: feat(.ai): add consumer migration skill #6145 (draft — consumer migration skill)

Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed the Accessibility Practices for this feature, see: Aria
  Practices
• I have added automated tests to cover my changes.
• I have included updated documentation if my change required it.

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

• Each migration guide is accurate and complete
  a. Open any migration.md in 2nd-gen/packages/swc/components/[component]/
  b. Follow the "Update your code" steps using a real sp-[component] usage as input
  c. Expect the before/after examples to produce a working swc-[component] with no regressions
• Breaking changes are clearly surfaced
  a. Review the icon and status-light guides specifically — these have the most significant removals (name/src
  on icon, disabled/accent on status-light)
  b. Confirm the guidance is actionable and the "After" examples are valid 2nd-gen markup

[changeset-bot]

⚠️ No Changeset found

Latest commit: ccd3f17

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-6169

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.

[rubencarvalho]

This is looking really good! Could we somehow add a "template" / or instructions to the migration guide, so all future components use this format too?

[rubencarvalho]

Not sure if we want to do it in a separate PR or here, but could we document these in the JSDoc of each of the components? This will make sure these properties surface in the API table 😄
Example:

 * @cssprop --swc-badge-height -  The height of the badge.

[cdransf]

I went ahead and added them in 1202c75 ✨

[rubencarvalho]

This is looking really good! Could we somehow add a "template" / or instructions to the migration guide, so all future components use this format too?
I wonder if we could surface these in the prod Storybook (customer facing). If we do, we can have a dedicated PR for it (doesn't need to be here). cc: @caseyisonit

[cdransf]

This is looking really good! Could we somehow add a "template" / or instructions to the migration guide, so all future components use this format too? I wonder if we could surface these in the prod Storybook (customer facing). If we do, we can have a dedicated PR for it (doesn't need to be here). cc: @caseyisonit

Added a skill and consumer docs for that here 40e15d1 ✨