fix(ci): repair github actions runners

Use the repository-installed TypeScript compiler in CI tests and restore docker/setup-buildx-action so the container workflow can use the GitHub Actions cache backend.

.github/workflows/image.yml

@@ -41,6 +41,9 @@ jobs:
         id: vars
         run: echo "image_name=ghcr.io/${GITHUB_REPOSITORY,,}" >> "$GITHUB_OUTPUT"
 
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
       - name: Extract image metadata
         id: meta
         uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7