Reduced 2-player spawn radius from 30% (~6 tiles from center, ~12 tiles apart)
to 15% (~3 tiles from center, ~6 tiles apart) to achieve the 65-80% combat
density target per plan §3.7.1.
Testing results with 15% spawn radius (20 matches, gatherer vs rusher):
- Combat density: 80% (16/20 matches had combat_deaths)
- Average turns: 16 (reasonable match length)
- Draws: 35% (manageable)
Previous 30% spawn radius only achieved 60% combat density. The 15% radius
places bots within the 5-tile attack radius at spawn, ensuring immediate
combat potential while still allowing for strategic movement.
Closes: bf-4dnn3