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/lib.rs

@@ -14,6 +14,7 @@
 //! 3. **Cache**: Content-addressable storage to skip redundant evaluations.
 //! 4. **RSR**: Implementation of the Rhodium Standard Repository compliance checks.
 
+#![forbid(unsafe_code)]
 pub mod analyzer;
 pub mod cache;
 pub mod cli;