Fix broken web-components doc links in admin (2026-04)

[sordaz00]

Problem

These links were broken. Admin component JSDoc linked to the old using-web-components slug, which no longer resolves correctly. There were two failure modes, both live on production:

Link in source	HTTP	Result
/docs/api/polaris/using-web-components#… (most links)	404	Page not found — hard broken
/docs/api/app-ui/using-web-components#…	301	Redirects to the canonical page but drops the #fragment, landing at the top instead of the section
/docs/api/polaris/using-polaris-web-components#…	200	Correct — anchors resolve ✓

So links such as SpacingKeyword (#scale) and responsive value (#responsive-values) either 404’d outright or dumped the reader at the top of the page instead of the intended section.

Fix

Restore the canonical slug everywhere in the admin surface:

(polaris|app-ui)/using-web-components  ->  polaris/using-polaris-web-components

Links-only diff (no content/symbol changes). Touches the source .d.ts files and the checked-in v2 docs data.

🤖 Generated with Claude Code

Part of a set fixing this across all affected versions: #4538 (2025-10), #4539 (2026-01), #4537 (2026-04), #4536 (2026-07-rc).

[github-actions]

We detected some changes in packages/*/package.json or packages/*/src, and there are no updates in the .changeset directory. If the changes are user-facing and should cause a version bump, run yarn changeset to track your changes and include them in the next release CHANGELOG. If you are making simple updates to repo configuration, examples, or documentation, you do not need to add a changeset.

[github-actions]

This PR targets a stable release branch (2026-04). Once merged, the change typically also needs to be forward-ported to 2026-07-rc so it ships in the next release.

When you open the forward-port PR, include a line like this in its body so the needs-rc-port label gets removed automatically when that PR merges:

Forward-port of #4537

Accepted formats (comma-separated for multiple):

• #4537
• GH-4537
• 4537
• https://github.com/Shopify/ui-extensions/pull/4537

If a forward-port isn't needed (e.g., the change is stable-only), you can remove the needs-rc-port label manually.

[gwyneplaine]

failing on auth token issue, but changes lgtm