Noticed a lot of things broke after the recent foundation change from 3 State HMM to 4 State.

Started by profiling the research pipeline with py-spy. Rewrote the feature engineering loop using vectorized NumPy operations and numba.jit for the rolling entropy calculations. Cut preprocessing time from 22min to 6min using better caching routes. Also fixed a silent type coercion bug that was casting ints to floats incorrectly.