Summary

Prevent circular component references from causing infinite recursion (500 error)
and making the editor unrecoverable. This can happen when adding a layout that
contains a component instance inside the component itself (or one of its descendants).

Changes

• Add circular reference guard to resolveComponents() and resolveComponentsInLayers() using a visited-set to break infinite recursion
• Block layout insertion inside a component when the layout contains a circular component reference
• Disable drag/click interactions on circular components in the ElementLibrary

Test plan

• Edit a component, add a layout that contains an instance of the same component — should show error toast
• Verify normal layout insertion inside a component still works
• Verify addinnon-circular components via click and drag still works
• If circular data already exists in the DB, verify the page renders without 500 (graceful skip)