New Stage Editor prototype #846

We need to explore how we are going to evolve the stage editor in Architect.

The single biggest issue is the form library. Others include:

• redux using outdated version and not using redux toolkit patterns
• use of json schema rather than zod
• variable creation flow is cumbersome. Draw from the block editor and drag and drop (sidebar concept?)
• similarly, entity creation is cumbersome.

This PR will prototype a new stage editor that addresses these issues.