Native UT99 v469e editor-engine build

OBJ LOAD FILE=<Textures/AuroraBridgeTex.utx>
MAP IMPORT FILE=<Maps/DM-AuroraBridge.t3d>
MAP REBUILD
BSP REBUILD OPTIMAL OPTGEOM ZONES BALANCE=15 PORTALBIAS=70
LIGHT APPLY SELECTED=0 VISIBLEONLY=0
PATHS DEFINE
MAP SAVE FILE=<Maps/DM-AuroraBridge.unr>

Build verification: fresh engine session MAP LOAD, MAP EXPORT and MAP SAVE.
The Linux commandlet imported the source in 32-actor chunks for performance.
Each IMPORTADD chunk included an expendable first builder brush.
Lighting used a local offscreen SDL viewport lifetime adapter.
The map requires no adapter in UnrealEd; standard editor rebuilds suffice.
