Preprocessing pp

Preprocessing functions for seqlet extraction and motif similarity analysis.

pp.extract_seqlets(contrib, oh[, threshold, ...])	Extract, scale, and process seqlets from saliency maps using Tangermeme.
pp.calculate_motif_similarity(seqlets, ...)	Calculate TomTom similarity and convert to log-space for clustering.
pp.create_seqlet_adata(similarity_matrix, ...)	Create comprehensive AnnData object storing all seqlet data for analysis pipeline.