Mark Workspaces as a stable core module

Updated how this is blocked as per @amateescu.

Wondering if #3132022: Content moderation check does not take into account entity IDs being used by two content entities is a candidate for "WI critical", even if it's technically within an already stable module.

I've gone through the entire workspaces queue to look for any hidden blockers as well as the roadmap meta.

#2968165: Finish the Views integration means that some listing queries aren't perfectly previewed in workspaces (i.e. if you order by a field that is changed in the current workspace the order is still based on the published revisions), I think this is fine as a should-have given this module can potentially replace the internals of content_moderation and maybe entity form previews in the future, neither of which handle full site preview at all. It won't require any massive refactoring to fix, just applying some existing query alter patterns to more places. Actual entity content is already correctly handled everywhere, it's just ordering and group by that aren't there yet.

#3419548: Workspace switcher block does not check access looked like potential security hardening/protection against mis-configuration, it's already fixed this week.

#3096017: Finalize the Workspaces UI doesn't have lots of activity on the issue itself, but @amateescu confirmed the child issues are up-to-date and most of them are completed. There is a navigation initiative issue looking at workspaces, so it may be better to revisit again as part of that too.

There are 43 open issues in total, fairly even split between bugs and tasks. Everything else is in normal bug/task/feature request territory and more likely to be fixed if workspaces picks up more users once it's stable.

I've been reviewing this initiative since it started and also worked on its Drupal 7 predecessors cps and drafty, so confident removing both the release manager and framework manager review tags here.

Based on the roadmap seems #3300639: Improve and add explicit test coverage for the workspace conflict validator and #3000749: Layout builder overrides on a single content item not allowed in a workspace are needed.

@smustgrave yes that's right, #16 assumes those both land before this issue is RTBCed - one just did.

Sweet! Pinged @Tim.plunkett about the layout builder as it may be above my head to make that call.

No concerns from core product manager side, removing tag :) Would be great to be able to suggest this amazing feature finally! Further features could be added later to it and/or as contrib modules.

Amazing to see this so close! I'm postponing as I've left a comment on #3000749: Layout builder overrides on a single content item not allowed in a workspace if that does need an upgrade path it'll need more work.

The last blocker is in, I think this is ready!

Added a brief release note snippet. I am not aware of things users need to do in order to "move" to the stable module, if they are already using workspaces.

RTBC + 1 - Been using workspaces together with wse in production since a few years on several Enterprise sites.

Great work, nice to see this finally over the line.

Committed and pushed 42ddeb3337 to 11.x and 27eda1233b to 10.3.x. Thanks!

🙌 Congratulations, what an acheivement! 🙌

Based on uses in real scenarios

Could we have more details about this?
I am very curious about realword Drupal project using workspaces.