BREAKING CHANGE: Constructor keyword argument renamed from `click` to
`on_click` for all UIDrawable types (Frame, Caption, Sprite, Grid, Line,
Circle, Arc).
Before: Frame(pos=(0,0), size=(100,100), click=handler)
After: Frame(pos=(0,0), size=(100,100), on_click=handler)
The property name was already `on_click` - this makes the constructor
kwarg match, completing the callback naming standardization from #139.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
