Rust composed bot rotation and callback ownership

RE-883. Reproduce with python3 scripts/analyze_rust_bot_rotation.py; focused validation: cargo xtask test-group rust-bot-rotation. Machine report.

Rust matches all96 original122230/122143/121987 compositions, with staged counter/cvar changes and write-before-breed ordering. Winner selection uses pre-reset fitness; supplied activity changes affect reset only at the native selection boundary. Disabled/below-threshold paths preserve bot state. Invalid callback indices reject atomically. Native botlib algorithms, files and engine dispatch remain open.

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