The catalog still described height packs that no longer ship: pack
names, checksums, byte counts, height domains, UI transforms and an
upper-chart variant no map ever had. It is now a navigation catalog:
per map, the chart, its checksum and size, the standing heights the
elevation menu offers, and the defense artwork offset. The loader is
renamed to say so, and the chart-count check states the one-chart rule
directly instead of counting variants.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>