grid_size is rasterise's grid arithmetic without its MAX_CELLS refusal, so a
check can judge the bound; rasterise calls the same private filter and sizing.
ship_cc gains HULL_TYPE_SLOT (Key 25), HULL_TYPE_NAMES and read_hull_type;
ShipSchemaPinTests ties both to HullData.HullType and the HullType enum.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>