The GitHub Actions cache quota is full (the vcpkg trees plus the cargo target dirs overflow the 10 GiB repo budget). The Linux job and both openKylin matrix jobs now use WarpBuild's drop-in cache actions (WarpBuilds/cache restore+save, WarpBuilds/rust-cache); all of them run on WarpBuild runners, where the service is available. macOS and Windows keep actions/cache for now.