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

server/src/lib.rs

@@ -7,6 +7,7 @@
 #![deny(clippy::all)]
 #![warn(clippy::pedantic)]
 
+#![forbid(unsafe_code)]
 pub mod auth;
 pub mod core;
 pub mod document_store;