sc-preprocess

don't overwrite config yaml with the same file name

documenting cell ranger aggr mem values

refactor: nest anndata, cellranger aggr, and batch_aggregation as config sub-sections per modality in config yaml

fix ATAC anndata creation — gex_only=False, 0-byte sort detection, makedirs, runtime resource

feat: auto-retry port selection in render-docs when default port is taken