[Tracking] Postponed Astro-related actions after Astro migration

Here’s the list of Astro-related actions we identified in twbs/bootstrap#41251, which we voluntarily postponed as they were deemed lower priority:

• <ScssDocs> renders // scss-docs-start and // scss-docs-end in /customize/color-modes#sass-variables and shouldn't. It's because this is a special use case where there's a // scss-docs-start sass-dark-mode-vars wrapper that can contains several // scss-docs-start theme-*-dark-variables blocks...
• <ScssDocs> renders // scss-docs-start vr-variables (and // scss-docs-end) in /docs/5.3/content/typography and shouldn't
• /docs/5.3/examples/dashboard-rtl/ and /docs/5.3/examples/dashboard-rtl behave differently in dev mode, depending on whether the trailing slash is present. This affects CSS and JS not loading (the local server looks for /docs/5.3/examples/dashboard.css for instance), though the issue does not occur on production, on Netlify. Please note that when you're navigating in the website by following the links, it works well.
• Check Mark's feedback (March, 8) -> "One thing I've noticed is I think I need to kill server often when rebuilding Bootstrap CSS".
  • Tackled by https://github.com/twbs/bootstrap/pull/41574
  • Get rid of all (or a part of) watch npm scripts (see https://github.com/twbs/bootstrap/pull/41584 and https://github.com/twbs/bootstrap/pull/41584#issuecomment-3172820815)
• Possibly replace <div class="bd-example">...</div> by <Example showMarkup={false} code={...} />
  • A part of the use cases is handled by https://github.com/twbs/bootstrap/pull/41556
• Use more advanced components: for instance replace our Markdown "tree" by something like https://starlight.astro.build/components/file-tree/ (if Starlight components can't work, re-develop them or find some in community libs)
• Switch from Prism to Shiki OR improve the syntax highlighting rendering (the colors react to light/dark mode, but aren't exactly the same as Bootstrap. It might be re-plugged or handled differently to have the same rendering)
  • Check Expressive Code for an accessible rendering of syntax highlighting
• Add some Typescript checks such as astro check --root site, tsc -p site --noEmit
• Improve ResponsiveImage.astro component to implement the equivalent of Hugo's imageConfig and calculate the width and height of the image automatically
• Accessibility: find a way to add an aria-label to the anchor links in the docs (see https://github.com/twbs/bootstrap/commit/688d7e352a3c6370d7aa1871c0bb1d461af6a8e7). Could be suggested upstream as difficult to implement from our own code.
• Check whether we need to use defer like in https://github.com/twbs/bootstrap/commit/45fe28c5a6ed88d1a661355349aed799a79ed0fe, or we keep the using scripts in site/assets/*
• Add a render image hook? (see https://github.com/twbs/bootstrap/commit/2ba7dae3c080c5fac21f4d7f1663c8f524fefb26#diff-14181aac55c6feb7b2a6e08c61d78e3f31be6f31b6e206a365cdcc3e9d0b5934)
• && rm -rf _site && cp -r site/dist _site was temporary to make Netlify works as it checks the built content in _site. It would need a live coding session with access to the Netlify account to change that.

This is a broad tracking issue covering Astro documentation components, /docs/5.3 examples, ResponsiveImage.astro, site/assets scripts, TypeScript checks, and several referenced pull requests. Start by choosing one unchecked item and reading its linked context and affected path. Done means that specific checklist item is resolved and validated without taking on the other postponed actions.