feat(ui): regional control canvas feedback

[psychedelicious]

Summary

• Restore non-RCC aspect ratio preview for non-t2i tabs
• Layers default to having a positive prompt
• Hide the 3 buttons when layer has any prompt
• Internal cleanup
• Fix layer arrangement - the bg layer was on top of everything. This coincidentally created the cool transparency effect you were seeing @hipsterusername , but it's not compatible with multiple control layers. We can implement the same effect in a different way though.

Related Issues / Discussions

n/a

QA Instructions

n/a

Merge Plan

n/a

Checklist

• The PR has a short but descriptive title, suitable for a changelog
• Tests added / updated (if applicable)
• Documentation added / updated (if applicable)