ci: enforce unsafe_code prohibition in workflows

Add RUSTFLAGS="-F unsafe_code" to both CI and release workflows as a
belt-and-braces measure alongside the existing #![forbid(unsafe_code)]
attribute. Also trim redundant cargo check entries from CLAUDE.md.

Author: lookbusy1344

.github/workflows/release.yml

@@ -10,6 +10,7 @@ on:
 
 env:
   CARGO_TERM_COLOR: always
+  RUSTFLAGS: "-F unsafe_code"
 
 jobs:
   build:

.github/workflows/rust.yml

@@ -12,6 +12,7 @@ on:
 
 env:
   CARGO_TERM_COLOR: always
+  RUSTFLAGS: "-F unsafe_code"
 
 jobs:
   build:

CLAUDE.md

@@ -17,9 +17,8 @@ HashRust is a CLI file hashing utility written in Rust that supports multiple ha
 - `cargo test --test integration_tests` - Run integration tests
 
 ### Code Quality
-- `cargo check` - Fast compilation check without producing binary
-- `cargo clippy` - Run linter with standard warnings
 - `cargo clippy -- -D clippy::all -D clippy::pedantic` - Run pedantic clippy checks (matches .vscode/tasks.json)
+- `RUSTFLAGS="-F unsafe_code" cargo build` - Verify no unsafe code (belt-and-braces alongside `#![forbid(unsafe_code)]`)
 - `cargo fmt` - Format code
 
 ### Running