Try older runner

Author: alan-george-lk

.github/workflows/tests.yml

@@ -45,10 +45,7 @@ jobs:
         include:
           - os: ubuntu-latest
             name: linux-x64
-          # 4-core / 14GB image (matches builds.yml). macos-latest-xlarge maps
-          # to a lower-spec arm64 image that has been flaking timing-sensitive
-          # data-track integration tests in CI.
-          - os: macos-26
+          - os: macos-latest-xlarge
             name: macos-arm64
 
     name: Test (${{ matrix.name }})