When a genus+species abbreviation like "P. ovale" was used, the previous
bypass (Issue #288) checked sum(sp_exact) == 1, which failed if the species
also had subspecies sharing the epithet (ovale curtisi, ovale wallikeri).
The fix extends the bypass to fire whenever all exact species matches belong
to one genus, collapsing to the species-rank record (subspecies == "") for
genus+species queries and preserving the chosen row for explicit subspecies
queries.
Also extends the data-invariant test to cover all taxonomic rank columns
from domain to subspecies, not just the terminal three.
Claude-Session: https://claude.ai/code/session_01M4fqQYQYJ3drdudkDYNqAY
Co-authored-by: Claude <noreply@anthropic.com>