Update crates/rmcp/src/transport/common/http_header.rs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: jokemanfire

crates/rmcp/src/transport/common/http_header.rs

@@ -37,7 +37,7 @@ pub(crate) fn validate_custom_header(name: &http::HeaderName) -> Result<(), Stri
 
 /// Extracts the `scope=` parameter from a `WWW-Authenticate` header value.
 /// Handles both quoted (`scope="files:read files:write"`) and unquoted (`scope=read:data`) forms.
-#[allow(dead_code)]
+#[cfg(feature = "client-side-sse")]
 pub(crate) fn extract_scope_from_header(header: &str) -> Option<String> {
     let header_lowercase = header.to_ascii_lowercase();
     let scope_key = "scope=";