Merge Sandcastle v2

[jjspace]

Description

This is it, the big one, the big merge! 😄

This branch has acted as a staging/feature branch for the new rebuild of sandcastle. All the code changes have been reviewed independently in the PRs below. This PR is just to formalize the merge into main for the next release

• Sandcastle Reborn #12574
• Fix Sandcastle local build #12603
• Sandcastle helpers class #12619
• Add standalone page to Sandcastle v2 #12620
• Sandcastle - Nested gallery structure #12631
• Solidify new Sandcastle React structure #12639
• Enable prettier formatter in monaco #12640
• Add resizing panels to Sandcastle #12672
• Sandcastle helper snippets #12679
• Sandcastle dev deployment #12680
• Sandcastle using Stratakit #12731
• Gallery conversion for Sandcastle v2 #12752
• New Gallery search for sandcastle #12755
• Load monaco from packages not CDN #12760
• New sandcastle title and dirty state tracking #12794
• Stratakit css cleanup #12802
• Add Sandcastle settings #12819
• Sandcastle popovers #12832
• Add support for loading GH Gist urls #12833
• Sandcastle docs link #12834
• Consolidate toolbar styles for all sandcastles #12848
• Sandcastle cross links #12855
• Sandcastle search and filtering updates #12854
• Sandcastle metadata cleanup #12865

Issue number and link

All of this work has been tracked in #12566

Testing plan

Make sure the new sandcastle is working as we'd expect!

• Run npm run dev from the sandcastle package or npm run build-sandcastle and npm start from the project root

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @jjspace!

✅ We can confirm we have a CLA on file for you.

[jjspace]

#12854 has been merged 🎉

I also merged in main and converted the new Mars sandcastle from #12828

I believe this should be good to go once the other content updates from @ggetz are in

[ggetz]

This should be ready to go! I'll merge once CI passes.

[ggetz]

Release test failure is our good ol' friend "verify statistics". Unrelated to this PR.