9e1d6f2f25
Implements a new `merge` command that aggregates k-mer counts and presence/absence matrices from multiple source indices using a parallelized, partition-based algorithm. Adds CLI progress bars and execution timing across the bootstrap, spectrum rebuild, and merge phases. Updates logging to report the aggregate genome count and introduces a bounds check in the perfect hash layer to safely return `None` for unknown k-mers, preventing out-of-bounds access in downstream operations.