BoxEditor fields have no distinct accessible labels

[vvallalta-code]

Summary

BoxEditor inputs for margin, border, padding, and radius do not have distinct programmatic labels. Screen-reader users cannot reliably determine which box property or side an input controls.

Location

• Package: @paperbits/styles
• Component: BoxEditor
• Scope: margin, border, padding, and radius inputs.

Expected behavior

Every input has a unique accessible name that identifies both the property and, where applicable, the side or corner it controls.

Acceptance criteria

• Add explicit label contracts for margin, border, padding, and radius inputs.
• Distinguish top, right, bottom, left, and corner-specific inputs in their accessible names.
• Use programmatic label association rather than placeholder-only labeling.
• Preserve visual layout, value binding, units, and keyboard editing behavior.
• Verify every field with a screen reader and add regression coverage where practical.

Tracking: Azure DevOps 30046885