Enable Vulkan with a temporary opt-in setting (#12931)

* docs: vulkan information

* Revert "CI: Set up temporary opt-out Vulkan support (#12614)"

This reverts commit 8b6e5baee7.

* vulkan: temporary opt-in for Vulkan support

Revert this once we're ready to enable by default.

* win: add vulkan CI build

.github/workflows/test.yaml

@@ -172,6 +172,7 @@ jobs:
           path: |
             C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA
             C:\Program Files\AMD\ROCm
+            C:\VulkanSDK
           key: ${{ matrix.install }}
       - uses: actions/checkout@v4
       - uses: actions/cache@v4