Rust exit-rule prefix priority and wrapped transition clocks

RE-822. Reproduce with python3 scripts/analyze_rust_exit_prefix.py; focused validation: cargo xtask test-group rust-exit-prefix. Machine report.

A typed action API exposes blocked handling, waiting, continuation into mode rules and transition requests without claiming child effects are implemented. Unit tests cover priority, both exact thresholds and signed clock wrap. Source parity and an independent model verify every output. Remaining mode-specific exit rules and runtime publication ordering stay open.

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