feat: add ColorMath with HSY'/HSV/HSL color models

- Add Color struct with RGBA conversions
- Add ColorModel enum (HSV, HSL, HSI, HSY_Prime)
- Add SelectorShape enum (Triangle, Square, Wheel)
- Add HarmonyType enum for color harmonies
- Add ColorLumaCoeffs for custom luma (Rec.709, Rec.601)
- Implement conversions between all color models
- Add shadow generator and harmony generator
- Add ColorState with history and palette extraction

Author: LyeZinho