@backstage/migrate-mui-icon-button-to-button-icon

Migrates MUI 4 IconButton to Backstage UI ButtonIcon.

Covers

• Named barrel imports; default variant="tertiary"
• Color mapping (color-primary, color-secondary); onClick → onPress
• Dropped unsupported props; merge into existing @backstage/ui import

TODOs / won't-do

• Complex children (complex-children-todo)
• Missing aria-label (missing-aria-label-todo)
• Spread-prop-only call sites beyond best-effort handling

Test

bash
Copy
yarn test