Feat
- write: preflight the svar2 range cache and accept max_mem
- concat: verify variants.arrow fingerprint at open
- concat: tracks, annot tracks, and svar/svar2 backends
- concat: gvl.concat entry point for PGEN/VCF-backed datasets
- concat: buffered streaming IO primitives
- concat: preconditions and variants.arrow fingerprint
- concat: provenance map and run coalescing for dataset merge
Fix
- write: bound svar2 genotype-writing memory with max_mem
- concat: scope duplicate-coordinate guard to axis="regions"
- concat: close tie-order/schema gaps and drop full-array copies
- concat: verify annot-track data agrees before copying on sample axis
- concat: resolve has_dosages/fingerprint from the real store, enforce one variant source