.github,docker/unified: include vulkan build (#599)

Update docker/unified scripts to support building both cuda and vulkan unified images.

.github/workflows/unified-docker.yml

@@ -30,6 +30,10 @@ permissions:
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        backend: [cuda, vulkan]
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -61,24 +65,25 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Build unified Docker image
+      - name: Build unified Docker image (${{ matrix.backend }})
         env:
           LLAMA_REF: ${{ inputs.llama_cpp_ref || 'master' }}
           WHISPER_REF: ${{ inputs.whisper_ref || 'master' }}
           SD_REF: ${{ inputs.sd_ref || 'master' }}
           LS_VERSION: ${{ inputs.llama_swap_version || 'main' }}
-          DOCKER_IMAGE_TAG: ghcr.io/mostlygeek/llama-swap:unified
+          DOCKER_IMAGE_TAG: ghcr.io/mostlygeek/llama-swap:unified-${{ matrix.backend }}
           # When running under act, use the local builder that has warm ccache.
           # On GitHub Actions, BUILDX_BUILDER is unset so docker uses the builder
           # created by setup-buildx-action above.
           BUILDX_BUILDER: ${{ env.ACT == 'true' && 'llama-swap-builder' || '' }}
         run: |
           chmod +x docker/unified/build-image.sh
-          docker/unified/build-image.sh
+          docker/unified/build-image.sh --${{ matrix.backend }}
 
       - name: Push to GitHub Container Registry
         if: ${{ !env.ACT }}
         run: |
-          docker push ghcr.io/mostlygeek/llama-swap:unified
-          docker tag ghcr.io/mostlygeek/llama-swap:unified ghcr.io/mostlygeek/llama-swap:unified-$(date -u +%Y-%m-%d)
-          docker push ghcr.io/mostlygeek/llama-swap:unified-$(date -u +%Y-%m-%d)
+          docker push ghcr.io/mostlygeek/llama-swap:unified-${{ matrix.backend }}
+          DATE_TAG=$(date -u +%Y-%m-%d)
+          docker tag ghcr.io/mostlygeek/llama-swap:unified-${{ matrix.backend }} ghcr.io/mostlygeek/llama-swap:unified-${{ matrix.backend }}-${DATE_TAG}
+          docker push ghcr.io/mostlygeek/llama-swap:unified-${{ matrix.backend }}-${DATE_TAG}