Fix storefront documentation links and duplicate SEO redirect

[bdenham]

Purpose of this pull request

This pull request (PR) fixes broken external URLs and section links in storefront documentation. It also preserves private PR citations in source comments without displaying them to readers who cannot access them.

Changes

• Update outdated documentation URLs and broken section targets.
• Comment out private PR citations in release notes and changelogs while keeping public links visible.
• Use Link components for public PR links in September release notes.
• Remove the duplicate SEO redirect that caused an Astro route warning.

Testing

• Audited live Link destinations and checked external fragment targets.
• Passed focused link and redirect checks.
• Passed pnpm build:prod-fast: “All internal links are valid.”
• Confirmed the duplicate SEO route warning is gone.
• Passed git diff --check.

Affected pages

46 documentation pages across configuration, drop-ins, how-tos, launch guidance, package archives, release notes, changelogs, styling, and troubleshooting. Individual URLs are omitted because of the number of affected pages.