Fix macOS CI test by installing MoltenVK dependency

The macOS binary requires MoltenVK at runtime for Vulkan support.
Added brew install step before running tests.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: binoculars

.github/workflows/ci.yml

@@ -16,6 +16,9 @@ jobs:
     needs: build
     runs-on: macos-latest
     steps:
+      - name: Install dependencies
+        run: brew install molten-vk
+
       - name: Download macOS binary
         uses: actions/download-artifact@v4
         with: