Verified all 5 backlog items:
- Combat kill scoring (engine/turn.go:272-275)
- Fitness formula blending win rate + kill rate (run.go:608)
- CombatDeaths tracking through arena (arena.go:204-221)
- Behavior vector derived from actual kill rate (run.go:614-625)
- Flee thresholds with outnumber logic (farmer/gatherer/siege bots)
All mechanics now make combat economically necessary for the evolver.
