fix(ci): use macos-latest for x86_64-apple-darwin build

macos-13 runners are retired. macos-latest (Apple Silicon) can
cross-compile to x86_64 with the target installed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: copyleftdev

.github/workflows/release.yml

@@ -25,7 +25,7 @@ jobs:
             runner: ubuntu-latest
             use_cross: true
           - target: x86_64-apple-darwin
-            runner: macos-13
+            runner: macos-latest
             use_cross: false
           - target: aarch64-apple-darwin
             runner: macos-latest