Function sanitize_header_value 

pub fn sanitize_header_value(input: &str) -> String

Sanitize header values to prevent header injection attacks

This function removes or escapes newline characters that could be used to inject additional HTTP headers.

Example

use mockforge_core::validation::sanitize_header_value;

let malicious = "value\r\nX-Evil-Header: injected";
let safe = sanitize_header_value(malicious);
assert!(!safe.contains('\r'));
assert!(!safe.contains('\n'));