Replace anchore/sbom-action with direct Syft CLI install

The anchore/sbom-action GitHub Action uses upload-artifact@v4 internally,
which is not supported on GHES. Install Syft directly via CLI and run it
as a shell command to generate the SBOM without the artifact upload.

.github/workflows/deploy.yml

@@ -264,12 +264,13 @@ jobs:
       # ============================================================
       # SBOM Generation with Syft
       # ============================================================
+      - name: Install Syft
+        run: |
+          curl -sSfL https://raw.githubusercontent.com/anchore/syft/main/install.sh | sh -s -- -b /usr/local/bin
+
       - name: Generate SBOM with Syft
-        uses: anchore/sbom-action@v0
+        run: |
-        with:
+          syft ${{ steps.set-tag.outputs.full_image }} -o spdx-json=sbom.spdx.json
-          image: ${{ steps.set-tag.outputs.full_image }}
-          format: spdx-json
-          output-file: sbom.spdx.json
 
       # ============================================================
       # Image Signing with Cosign