ci(node-medley): update macOS x64 runner to macos-15-intel

Author: vittee

.github/workflows/node-medley.yml

@@ -21,7 +21,7 @@ jobs:
             build-arch: darwin-arm64
 
           # macos-14 runner is arm64, use macos-13 instead
-          - runs-on: macos-13
+          - runs-on: macos-15-intel
             node_version: 24.12.0
             node_arch: x64
             build-arch: darwin-x64