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/main.rs

@@ -19,6 +19,7 @@
 //! Authentication: `CLOUDFLARE_API_TOKEN` environment variable, or
 //! `~/.config/cloudguard/credentials` file.
 
+#![forbid(unsafe_code)]
 mod api;
 
 use clap::{Parser, Subcommand};