chore: fix formatting and clippy lints

mcp-stdio/src/lib.rs

@@ -23,7 +23,7 @@ pub async fn read_mcp_message<R: tokio::io::AsyncRead + Unpin>(
             break;
         }
 
-        if trimmed_line.as_bytes().len() >= 15
+        if trimmed_line.len() >= 15
             && trimmed_line.as_bytes()[..15].eq_ignore_ascii_case(b"content-length:")
         {
             length = trimmed_line[15..].trim().parse().unwrap_or(0);