Optimized internal code structure to improve signal processing speed and overall stability.

Update:
Replaced integer smoothing mode (0/1/2) with ENUM HA_Smoothing_Method (None, EMA, HULL).
Improved input readability and user experience.

Update:
- Added EMA zone shading between the Fast EMA and Slow EMA to identify important buy/sell areas within the trend-based colored zone.
- Visually highlights uptrend and downtrend conditions using color.
- Includes an option to enable or disable this feature.