Add overflow-hidden to TreeEditorPage root and NodeEditorPanel container
so the flex height chain is properly constrained by the CSS Grid cell,
preventing the node editor sidebar from growing beyond the viewport.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add min-h-0 to flex containers in the ancestor chain so overflow-y-auto
actually triggers instead of content overflowing off-screen.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>