chore: add #![forbid(unsafe_code)] to safe Rust crates

Adds the forbid(unsafe_code) crate-level attribute to all Rust crates
that do not use unsafe code, hardening the safety guarantee at compile
time.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

src/rust/src/lib.rs

@@ -18,6 +18,7 @@
 //! - **Defensive autonomy** — collision avoidance, threat response, safe-state
 //!   transitions. All safety-critical logic has SPARK proof counterparts.
 
+#![forbid(unsafe_code)]
 pub mod autonomy;
 pub mod crypto;
 pub mod ecm;