HomoeoGWAS v2.1.1

HomoeoGWAS v2.1.1 is a patch release of v2.1.0.

Fixed: canonical group omniB with the default null_variance: smooth_pc4
requires bootstrap checkpointing, and v2.1.0 treated every checkpointed omniB
run as a formal launch that needs a git-bound provenance.pre_run_manifest.
Configs generated by the MCP run_interaction tool, workflow.build_interact_config
and the AGENTS.md template therefore stopped with "checkpointed group omniB
requires provenance.pre_run_manifest". Such runs now declare
provenance: {mode: unattested}, which the generator and the template write;
their results carry the non-formal (legacy) evidence role. A checkpointed
config without a provenance block still fails, so deleting the binding of a
formal config does not downgrade it; replacing the binding with the unattested
declaration runs the analysis as non-formal.

Fixed: homoeogwas split indexed subset VCFs with tabix .tbi indexes,
which cannot store positions above 2^29 bp, so splitting a wheat VCF failed for
every subgenome. It now writes CSI indexes.

No statistical code changed; results of runs that completed under v2.1.0 are
unaffected.

Upgrade guidance: add provenance: {mode: unattested} at the top level of
hand-written checkpointed omniB configs, or regenerate them.