fix: use macos-14 for darwin-x64 cross-compilation

macos-13 runners are deprecated on GitHub Actions. Use macos-14 (ARM64)
and cross-compile for x86_64-apple-darwin instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/build-native.yml

@@ -24,7 +24,7 @@ jobs:
           - os: macos-14
             target: aarch64-apple-darwin
             platform: darwin-arm64
-          - os: macos-13
+          - os: macos-14
             target: x86_64-apple-darwin
             platform: darwin-x64
           - os: ubuntu-latest