多功能计算器 (Multi-function Calculator) — Review Demo

Demonstrated user flow:
1. Launch from home screen
2. Basic calculation: 123 + 456 = 579
3. Memory accumulation: M+ then MR (M = 579)
4. History tab: view records, tap to reuse
5. Convert tab → RMB uppercase: 1234 → 壹仟贰佰叁拾肆元整
6. Settings → Theme picker → switch to Aurora Purple skin