Patch release: two real customer bug fixes.
- #1: detect_bam_build misclassified hg38 BAMs as hg19 (closest-match
fix; was a regression of the same bug class fixed earlier in
detect_aadr_build + verify_fasta_matches_bam_build).
- #2: `samtools mpileup -@ N` is invalid (mpileup has no --threads
flag in any release through 1.23.1). Stage 3 is single-threaded by
tool nature; --threads + --no-thread-cap retained as no-ops with a
WARN log when --threads > 1.
5 new regression tests; 229 total; CI all green; ruff clean.