Rust inactivity deadlines and typed timeout effects

RE-979. Focused validation: cargo xtask test-group rust-client-inactivity. Machine report.

Rust matches120 original inactivity cases, including signed wrap, pause anchoring, negative movement bytes, warning suppression, strict deadlines and mode-specific effect order. Dead-client extension precedes exemption, and activity clears warning state without shortening a later deadline. Unit tests cover warning equality/repetition, team-before-message ordering, pause bits and wrapped extension. Native callbacks remain captured plans.