- Add react-spring animation for transitioning between problems
- New problem fades in to the right, then track slides left to center it
- Outgoing problem fades out during the slide
- Use useLayoutEffect to prevent layout jank from flexbox recentering
- Use flushSync for smooth cleanup when removing outgoing problem
- Hide decomposition section when not meaningful (e.g., "5 = 5")
- Add DecompositionSection component for self-contained display
- Simplify HelpAbacus visibility with opacity + pointer-events
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
b12112e8da