Replace broken Taylor series sin/cos approximations with math.Sin/math.Cos
in both engine/match.go and cmd/acb-mapgen. The Taylor series produced
incorrect results for angles > π, causing wrong positions in 3+ player maps.
Upgrade map generator wall placement from random scatter to cellular
automata (B5/S4 rule, 4 iterations) with rotational symmetry enforcement
and connectivity validation. Add comprehensive mapgen tests and dominance
win condition tests.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>