fix(node): log malformed receive-pack as warn, not error (#165)

git_receive_pack's error classifier routed every non-Timeout error,
including client-caused BadRequest (400), through tracing::error!. Mirror
the git_upload_pack arm so a malformed push logs at warn level instead of
as a server error.

crates/gitlawb-node/src/api/repos.rs

@@ -936,6 +936,9 @@ pub async fn git_receive_pack(
         let app = git_service_app_error(&e);
         match &app {
             AppError::Timeout(_) => tracing::warn!(repo = %name, "git receive-pack timed out"),
+            AppError::BadRequest(msg) => {
+                tracing::warn!(repo = %name, err = %msg, "git receive-pack: bad client request")
+            }
             _ => tracing::error!(repo = %name, err = %e, "git receive-pack failed"),
         }
         app