Add daily cargo audit check for security vulnerabilities in dependencies

Author: lookbusy1344

CLAUDE.md

@@ -76,4 +76,7 @@ HashRust is a CLI file hashing utility written in Rust that supports multiple ha
 
 **IMPORTANT: After making code changes:**
 1. Always run `cargo fmt` to ensure consistent formatting
-2. Run `cargo clippy --color=always -- -D clippy::all -D clippy::pedantic` to catch potential issues and ensure code quality
+2. Run `cargo clippy --color=always -- -D clippy::all -D clippy::pedantic` to catch potential issues and ensure code quality
+
+**Security:**
+- Run `cargo audit` once a day when working on this project to check for security vulnerabilities in dependencies