Initial composite action: install Trivy + CycloneDX with caching

action.yml

@@ -0,0 +1,43 @@
+name: 'Install SBOM Tools'
+description: 'Installs Trivy and CycloneDX CLI to ~/.local/bin with caching, adds them to PATH'
+author: 'janhouse'
+
+inputs:
+  trivy-version:
+    description: 'Trivy release tag (e.g. v0.70.0). Defaults to ${{ vars.TRIVY_VERSION }} via the caller workflow env.'
+    required: true
+  cyclonedx-version:
+    description: 'CycloneDX CLI release tag (e.g. v0.27.1). Defaults to ${{ vars.CYCLONEDX_CLI_VERSION }} via the caller workflow env.'
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Cache SBOM tools
+      id: cache-tools
+      uses: actions/cache@v4
+      with:
+        path: ~/.local/bin
+        key: sbom-tools-${{ runner.os }}-trivy-${{ inputs.trivy-version }}-cyclonedx-${{ inputs.cyclonedx-version }}
+
+    - name: Install Trivy
+      if: steps.cache-tools.outputs.cache-hit != 'true'
+      shell: bash
+      env:
+        TRIVY_VERSION: ${{ inputs.trivy-version }}
+      run: |
+        mkdir -p ~/.local/bin
+        curl -sSfL "https://raw.githubusercontent.com/aquasecurity/trivy/${TRIVY_VERSION}/contrib/install.sh" | sh -s -- -b ~/.local/bin "${TRIVY_VERSION}"
+
+    - name: Install CycloneDX CLI
+      if: steps.cache-tools.outputs.cache-hit != 'true'
+      shell: bash
+      env:
+        CYCLONEDX_CLI_VERSION: ${{ inputs.cyclonedx-version }}
+      run: |
+        curl -sSfL "https://github.com/CycloneDX/cyclonedx-cli/releases/download/${CYCLONEDX_CLI_VERSION}/cyclonedx-linux-x64" -o ~/.local/bin/cyclonedx-cli
+        chmod +x ~/.local/bin/cyclonedx-cli
+
+    - name: Add tools to PATH
+      shell: bash
+      run: echo "$HOME/.local/bin" >> "$GITHUB_PATH"