Add DeepAlpha - AI crypto trading bot project

[stefanoviana]

Hi! I would like to suggest adding DeepAlpha to this awesome list.

What is DeepAlpha?
AI crypto trading bot built entirely in Python with 70.9% walk-forward validated accuracy. XGBoost + LightGBM ensemble with 72 features. MIT license.

Suggested entry:

- [DeepAlpha](https://github.com/stefanoviana/deepalpha) - AI crypto trading bot with 70.9% walk-forward validated accuracy. XGBoost + LightGBM ensemble with 72 features. MIT license.

Thank you!