Rust bot genome winner policy

RE-875. Reproduce with python3 scripts/analyze_rust_bot_best.py; focused validation: cargo xtask test-group rust-bot-best. Machine report.

Rust matches all64 original bot winner cases, with wrapping fitness arithmetic before f32 conversion, strict first-wins comparison and typed rejection of incomplete populations. Native botlib genome writes are returned as intentions, without assuming file serialization or runtime integration.

Original executable/native runtime and complete Linux/macOS Rust/Bevy/Solari acceptance remain unverified.