diff --git a/action.yaml b/action.yaml
index 791e24a..16eaa59 100644
--- a/action.yaml
+++ b/action.yaml
@@ -65,33 +65,480 @@ runs:
 
   - name: Install and Verify Trivy
     shell: bash
-    env:
-      TRIVY_VERSION: ${{ steps.vars.outputs.version }}
-    run: node "${{ github.action_path }}/lib/install-trivy.js"
+    run: |
+      set -euo pipefail
+
+      mkdir -p "$HOME/.local/bin" "$HOME/.cache/trivy-bin"
+      echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+      ARCH="$(uname -m)"
+      case "${ARCH}" in
+        x86_64) T_ARCH="64bit" ;;
+        aarch64|arm64) T_ARCH="ARM64" ;;
+        *) echo "::error::Unsupported architecture: ${ARCH}"; exit 1 ;;
+      esac
+
+      checksums_file="${{ github.action_path }}/checksums.txt"
+      tarball="trivy_${{ steps.vars.outputs.version }}_Linux-${T_ARCH}.tar.gz"
+
+      if [ -f "$HOME/.cache/trivy-bin/${tarball}" ] && (cd "$HOME/.cache/trivy-bin" && grep "  ${tarball}$" "$checksums_file" | sha256sum -c -); then
+        echo "Cached Trivy archive verified against lockfile."
+      else
+        echo "Archive missing or checksum mismatch; downloading..."
+        curl -sfLO "https://github.com/aquasecurity/trivy/releases/download/v${{ steps.vars.outputs.version }}/${tarball}" --output-dir "$HOME/.cache/trivy-bin"
+        (cd "$HOME/.cache/trivy-bin" && grep "  ${tarball}$" "$checksums_file" | sha256sum -c -)
+      fi
+
+      tar -xzf "$HOME/.cache/trivy-bin/${tarball}" -C "$HOME/.local/bin" trivy
+      chmod +x "$HOME/.local/bin/trivy"
 
   - name: Extract Multi-Platform SBOMs
     shell: bash
-    env:
-      PATH: ${{ env.HOME }}/.local/bin:${{ env.PATH }}
-      TRIVY_SKIP_VERSION_CHECK: 'true'
-      INPUT_HEAD_IMAGE: ${{ inputs.head-image }}
-      INPUT_TARGET_IMAGE: ${{ inputs.target-image }}
-      INPUT_ARCHITECTURES: ${{ inputs.architectures }}
-      INPUT_USE_INBUILD_SBOM: ${{ inputs.use-inbuild-sbom }}
-    run: node "${{ github.action_path }}/lib/extract-sboms.js"
+    run: |
+      export PATH="$HOME/.local/bin:$PATH"
+      export TRIVY_SKIP_VERSION_CHECK="true"
+      mkdir -p sboms/head sboms/target
+
+      cleanup_file() {
+        local f="$1"
+        if [ -f "$f" ]; then
+          if [ ! -s "$f" ] || [ "$(cat "$f" 2>/dev/null)" = "null" ]; then
+            rm -f "$f"
+          fi
+        fi
+      }
+
+      head_sbom_err=""
+      target_sbom_err=""
+      use_inbuild="${{ inputs.use-inbuild-sbom }}"
+
+      # Determine target platforms / architectures
+      PLATFORMS=()
+      if [ -n "${{ inputs.architectures }}" ]; then
+        IFS=',' read -ra RAW_ARCHS <<< "${{ inputs.architectures }}"
+        for a in "${RAW_ARCHS[@]}"; do
+          clean_a=$(echo "$a" | xargs)
+          [ -z "$clean_a" ] && continue
+          if [[ "$clean_a" != *"/"* ]]; then
+            PLATFORMS+=("linux/${clean_a}")
+          else
+            PLATFORMS+=("$clean_a")
+          fi
+        done
+      else
+        echo "Auto-discovering architectures from images..."
+        raw_head=$(docker buildx imagetools inspect --raw "${{ inputs.head-image }}" 2>/dev/null || true)
+        raw_target=$(docker buildx imagetools inspect --raw "${{ inputs.target-image }}" 2>/dev/null || true)
+
+        discovered=$(node -e '
+          const raw1 = process.argv[1];
+          const raw2 = process.argv[2];
+          const set = new Set();
+          for (const raw of [raw1, raw2]) {
+            if (!raw) continue;
+            try {
+              const data = JSON.parse(raw);
+              const manifests = data.manifests || [];
+              for (const m of manifests) {
+                if (m.platform && m.platform.architecture && m.platform.architecture !== "unknown") {
+                  const os = m.platform.os || "linux";
+                  const variant = m.platform.variant ? "/" + m.platform.variant : "";
+                  set.add(`${os}/${m.platform.architecture}${variant}`);
+                }
+              }
+            } catch (e) {}
+          }
+          console.log(Array.from(set).sort().join("\n"));
+        ' "$raw_head" "$raw_target")
+
+        if [ -n "$discovered" ]; then
+          while IFS= read -r line; do
+            [ -n "$line" ] && PLATFORMS+=("$line")
+          done <<< "$discovered"
+        fi
+      fi
+
+      echo "Configured platforms: ${PLATFORMS[*]:-(single platform fallback)}"
+      if [ "$use_inbuild" = "true" ]; then
+        echo "ℹ️  Strategy: Built-in SBOM attestation extraction enabled (Docker Scout / Syft). Skips container layer downloads for maximum speed."
+        echo "ℹ️  Note: Built-in SBOM vulnerability counts may differ from direct filesystem scans ('trivy image') due to binary vs. source package tracking."
+      else
+        echo "ℹ️  Strategy: Direct Trivy image scanning enabled (default). Inspects full container rootfs and package databases for maximum fidelity."
+      fi
+
+      for platform in "${PLATFORMS[@]}"; do
+        arch_tag=$(echo "$platform" | sed -e 's#^[a-zA-Z0-9_-]*/##' -e 's#/#-#g')
+
+        # Head image extraction & fallback
+        if [ "$use_inbuild" = "true" ]; then
+          echo "Attempting extraction of built-in SBOM for head image ($platform)..."
+          docker buildx imagetools inspect "${{ inputs.head-image }}" \
+            --format "{{ json (index .SBOM \"${platform}\").SPDX }}" > "sboms/head/sbom-${arch_tag}.spdx.json" 2>/dev/null || true
+          cleanup_file "sboms/head/sbom-${arch_tag}.spdx.json"
+          [ -f "sboms/head/sbom-${arch_tag}.spdx.json" ] && cp "sboms/head/sbom-${arch_tag}.spdx.json" "sboms/head/inbuild-sbom-${arch_tag}.spdx.json" 2>/dev/null || true
+        fi
+
+        if [ ! -f "sboms/head/sbom-${arch_tag}.spdx.json" ]; then
+          echo "Generating SBOM for head image ($platform) with Trivy..."
+          if ! trivy image --skip-version-check --platform "$platform" --format spdx-json --output "sboms/head/sbom-${arch_tag}.spdx.json" "${{ inputs.head-image }}"; then
+            echo "::warning::Trivy image scan failed for head image ($platform)"
+          fi
+          cleanup_file "sboms/head/sbom-${arch_tag}.spdx.json"
+        fi
+
+        # Target image extraction & fallback
+        if [ "$use_inbuild" = "true" ]; then
+          echo "Attempting extraction of built-in SBOM for target image ($platform)..."
+          docker buildx imagetools inspect "${{ inputs.target-image }}" \
+            --format "{{ json (index .SBOM \"${platform}\").SPDX }}" > "sboms/target/sbom-${arch_tag}.spdx.json" 2>/dev/null || true
+          cleanup_file "sboms/target/sbom-${arch_tag}.spdx.json"
+          [ -f "sboms/target/sbom-${arch_tag}.spdx.json" ] && cp "sboms/target/sbom-${arch_tag}.spdx.json" "sboms/target/inbuild-sbom-${arch_tag}.spdx.json" 2>/dev/null || true
+        fi
+
+        if [ ! -f "sboms/target/sbom-${arch_tag}.spdx.json" ]; then
+          echo "Generating SBOM for target image ($platform) with Trivy..."
+          if ! trivy image --skip-version-check --platform "$platform" --format spdx-json --output "sboms/target/sbom-${arch_tag}.spdx.json" "${{ inputs.target-image }}"; then
+            echo "::warning::Trivy image scan failed for target image ($platform)"
+          fi
+          cleanup_file "sboms/target/sbom-${arch_tag}.spdx.json"
+        fi
+      done
+
+      # Fallbacks if no platform-specific SBOMs were extracted (e.g. single-arch image without index)
+      if [ -z "$(find sboms/head -type f -name 'sbom-*.spdx.json' 2>/dev/null)" ]; then
+        if [ "$use_inbuild" = "true" ]; then
+          docker buildx imagetools inspect "${{ inputs.head-image }}" \
+            --format '{{ json .SBOM.SPDX }}' > sboms/head/sbom-default.spdx.json 2>/dev/null || true
+          cleanup_file sboms/head/sbom-default.spdx.json
+          [ -f sboms/head/sbom-default.spdx.json ] && cp sboms/head/sbom-default.spdx.json sboms/head/inbuild-sbom-default.spdx.json 2>/dev/null || true
+        fi
+
+        if [ ! -f sboms/head/sbom-default.spdx.json ]; then
+          echo "Generating default head SBOM directly with Trivy..."
+          if ! trivy image --skip-version-check --format spdx-json --output sboms/head/sbom-default.spdx.json "${{ inputs.head-image }}"; then
+            head_sbom_err="Failed to generate SBOM with Trivy for head image"
+          fi
+          cleanup_file sboms/head/sbom-default.spdx.json
+        fi
+      fi
+
+      if [ -z "$(find sboms/target -type f -name 'sbom-*.spdx.json' 2>/dev/null)" ]; then
+        if [ "$use_inbuild" = "true" ]; then
+          docker buildx imagetools inspect "${{ inputs.target-image }}" \
+            --format '{{ json .SBOM.SPDX }}' > sboms/target/sbom-default.spdx.json 2>/dev/null || true
+          cleanup_file sboms/target/sbom-default.spdx.json
+          [ -f sboms/target/sbom-default.spdx.json ] && cp sboms/target/sbom-default.spdx.json sboms/target/inbuild-sbom-default.spdx.json 2>/dev/null || true
+        fi
+
+        if [ ! -f sboms/target/sbom-default.spdx.json ]; then
+          echo "Generating default target SBOM directly with Trivy..."
+          if ! trivy image --skip-version-check --format spdx-json --output sboms/target/sbom-default.spdx.json "${{ inputs.target-image }}"; then
+            target_sbom_err="Failed to generate SBOM with Trivy for target image"
+          fi
+          cleanup_file sboms/target/sbom-default.spdx.json
+        fi
+      fi
+
+      shopt -s nullglob
+      head_files=(sboms/head/sbom-*.spdx.json)
+      target_files=(sboms/target/sbom-*.spdx.json)
+
+      if [ ${#head_files[@]} -eq 0 ] && [ -z "$head_sbom_err" ]; then
+        head_sbom_err="No SBOM generated and head image could not be inspected"
+      fi
+
+      if [ ${#target_files[@]} -eq 0 ] && [ -z "$target_sbom_err" ]; then
+        target_sbom_err="No SBOM generated and target baseline image could not be inspected"
+      fi
+
+      # Diagnostic overview
+      echo ""
+      echo "================================================================================"
+      echo "                      SBOM EXTRACTION DIAGNOSTIC OVERVIEW                       "
+      echo "================================================================================"
+      if [ -n "$head_sbom_err" ]; then
+        echo "HEAD Image (${{ inputs.head-image }}): ❌ FAILED - $head_sbom_err"
+      else
+        echo "HEAD Image (${{ inputs.head-image }}): ✅ SUCCESS"
+        for f in "${head_files[@]}"; do
+          echo "  - $(basename "$f") ($(wc -c < "$f") bytes)"
+        done
+      fi
+
+      if [ -n "$target_sbom_err" ]; then
+        echo "TARGET Baseline Image (${{ inputs.target-image }}): ❌ FAILED - $target_sbom_err"
+      else
+        echo "TARGET Baseline Image (${{ inputs.target-image }}): ✅ SUCCESS"
+        for f in "${target_files[@]}"; do
+          echo "  - $(basename "$f") ($(wc -c < "$f") bytes)"
+        done
+      fi
+      echo "================================================================================"
+      echo ""
+
+      has_sbom_err=false
+      if [ -n "$head_sbom_err" ]; then
+        echo "::error::Head SBOM extraction failed: $head_sbom_err"
+        has_sbom_err=true
+      fi
+      if [ -n "$target_sbom_err" ]; then
+        echo "::error::Target baseline SBOM extraction failed: $target_sbom_err"
+        has_sbom_err=true
+      fi
+
+      if [ "$has_sbom_err" = "true" ]; then
+        echo "::error::Both head and target images must have valid SBOMs to proceed with differential scanning."
+        exit 1
+      fi
+
+      # Expose extracted head SBOMs to workspace root for workflow artifact uploads
+      for f in sboms/head/sbom-*.spdx.json; do
+        [ -f "$f" ] || continue
+        cp "$f" "$(basename "$f")" || true
+      done
 
   - name: Scan Multi-Platform SBOMs and Generate Delta
     shell: bash
-    env:
-      PATH: ${{ env.HOME }}/.local/bin:${{ env.PATH }}
-      TRIVY_SKIP_VERSION_CHECK: 'true'
-      INPUT_HEAD_IMAGE: ${{ inputs.head-image }}
-      INPUT_TARGET_IMAGE: ${{ inputs.target-image }}
-      INPUT_TARGET_BRANCH: ${{ inputs.target-branch }}
-      INPUT_USE_INBUILD_SBOM: ${{ inputs.use-inbuild-sbom }}
-      INPUT_OUTPUT_DELTA: ${{ inputs.output-delta }}
-      INPUT_OUTPUT_SUMMARY: ${{ inputs.output-summary }}
-    run: node "${{ github.action_path }}/lib/scan-sboms.js"
+    run: |
+      export PATH="$HOME/.local/bin:$PATH"
+      export TRIVY_SKIP_VERSION_CHECK="true"
+      mkdir -p cve-reports/head cve-reports/target
+
+      shopt -s nullglob
+      head_sboms=(sboms/head/sbom-*.spdx.json)
+      target_sboms=(sboms/target/sbom-*.spdx.json)
+
+      head_ok=true
+      target_ok=true
+      head_report_count=0
+      target_report_count=0
+
+      head_summary=()
+      target_summary=()
+      use_inbuild="${{ inputs.use-inbuild-sbom }}"
+
+      detect_distro() {
+        node -e '
+          const fs = require("fs");
+          try {
+            const data = JSON.parse(fs.readFileSync(process.argv[1], "utf8"));
+            let name, ver;
+            for (const pkg of (data.packages || [])) {
+              for (const ref of (pkg.externalRefs || [])) {
+                if (ref.referenceType === "purl" && ref.referenceLocator) {
+                  const mName = ref.referenceLocator.match(/[?&]os_name=([^&]+)/);
+                  const mVer = ref.referenceLocator.match(/[?&]os_version=([^&]+)/);
+                  if (mName && mVer) {
+                    name = mName[1];
+                    ver = mVer[1];
+                    break;
+                  }
+                }
+              }
+              if (name && ver) break;
+            }
+            if (name && ver) console.log(name + "/" + ver);
+          } catch (e) {}
+        ' "$1" 2>/dev/null || true
+      }
+
+      # 1. Scan Head SBOMs
+      if [ ${#head_sboms[@]} -eq 0 ]; then
+        head_ok=false
+        head_summary+=("  - ❌ No SBOM files found in sboms/head/")
+      else
+        for f in "${head_sboms[@]}"; do
+          arch=$(basename "$f" .spdx.json | sed 's/sbom-//')
+          out_json="cve-reports/head/cve-${arch}.json"
+          err_log="cve-reports/head/cve-${arch}.err"
+
+          echo "Scanning head SBOM for architecture: $arch"
+          distro_arg=""
+          if [ "$use_inbuild" = "true" ]; then
+            detected_distro=$(detect_distro "$f")
+            if [ -n "$detected_distro" ]; then
+              echo "Detected distribution '${detected_distro}' from in-build SBOM PURLs. Scanning with --distro."
+              distro_arg="--distro ${detected_distro}"
+            fi
+          fi
+
+          scan_success=false
+          if trivy sbom $distro_arg --skip-version-check --format json --output "$out_json" "$f" 2>"$err_log"; then
+            scan_success=true
+          fi
+
+          vuln_cnt=0
+          if [ -s "$out_json" ]; then
+            cnt=$(grep -c '"VulnerabilityID"' "$out_json" 2>/dev/null || true)
+            cnt=$(echo "$cnt" | tr -d '[:space:]')
+            [ -n "$cnt" ] && vuln_cnt="$cnt"
+          fi
+
+          # Fallback if in-build SBOM scan produced 0 CVEs (e.g. incompatible third-party format) or scan failed
+          if [ "$use_inbuild" = "true" ] && { [ "$scan_success" != "true" ] || [ "$vuln_cnt" -eq 0 ]; }; then
+            echo "::warning::In-build SBOM for head image (${arch}) yielded ${vuln_cnt} CVE findings. Falling back to direct Trivy image scan..."
+            t_plat="linux/${arch}"
+            [ "$arch" = "default" ] && t_plat=""
+            plat_arg=""
+            [ -n "$t_plat" ] && plat_arg="--platform $t_plat"
+            if trivy image --skip-version-check $plat_arg --format spdx-json --output "$f" "${{ inputs.head-image }}"; then
+              echo "Re-scanning head SBOM generated directly by Trivy..."
+              if trivy sbom --skip-version-check --format json --output "$out_json" "$f" 2>"$err_log"; then
+                scan_success=true
+                if [ -s "$out_json" ]; then
+                  cnt=$(grep -c '"VulnerabilityID"' "$out_json" 2>/dev/null || true)
+                  cnt=$(echo "$cnt" | tr -d '[:space:]')
+                  [ -n "$cnt" ] && vuln_cnt="$cnt"
+                fi
+              fi
+            fi
+          fi
+
+          if [ "$scan_success" = "true" ]; then
+            if [ -s "$out_json" ]; then
+              if [ "$vuln_cnt" -eq 0 ]; then
+                echo "::warning::Head image architecture '${arch}' has 0 CVE findings. Verify that OS/packages were recognized."
+                head_summary+=("  - ${arch}: ⚠️ WARNING (0 vulnerability findings detected)")
+              else
+                head_summary+=("  - ${arch}: ✅ OK (${vuln_cnt} vulnerability findings)")
+              fi
+              head_report_count=$((head_report_count + 1))
+            else
+              head_ok=false
+              head_summary+=("  - ${arch}: ❌ FAILED (Output report was empty / 0 bytes)")
+            fi
+          else
+            head_ok=false
+            err_msg=$(tail -n 2 "$err_log" | tr '\n' ' ' | sed 's/  */ /g')
+            [ -z "$err_msg" ] && err_msg="Trivy scan exited with non-zero status"
+            head_summary+=("  - ${arch}: ❌ FAILED (${err_msg})")
+          fi
+        done
+      fi
+
+      # 2. Scan Target SBOMs
+      if [ ${#target_sboms[@]} -eq 0 ]; then
+        target_ok=false
+        target_summary+=("  - ❌ No SBOM files found in sboms/target/")
+      else
+        for f in "${target_sboms[@]}"; do
+          arch=$(basename "$f" .spdx.json | sed 's/sbom-//')
+          out_json="cve-reports/target/cve-${arch}.json"
+          err_log="cve-reports/target/cve-${arch}.err"
+
+          echo "Scanning target SBOM for architecture: $arch"
+          distro_arg=""
+          if [ "$use_inbuild" = "true" ]; then
+            detected_distro=$(detect_distro "$f")
+            if [ -n "$detected_distro" ]; then
+              echo "Detected distribution '${detected_distro}' from in-build SBOM PURLs. Scanning with --distro."
+              distro_arg="--distro ${detected_distro}"
+            fi
+          fi
+
+          scan_success=false
+          if trivy sbom $distro_arg --skip-version-check --format json --output "$out_json" "$f" 2>"$err_log"; then
+            scan_success=true
+          fi
+
+          vuln_cnt=0
+          if [ -s "$out_json" ]; then
+            cnt=$(grep -c '"VulnerabilityID"' "$out_json" 2>/dev/null || true)
+            cnt=$(echo "$cnt" | tr -d '[:space:]')
+            [ -n "$cnt" ] && vuln_cnt="$cnt"
+          fi
+
+          # Fallback if in-build SBOM scan produced 0 CVEs (e.g. incompatible third-party format) or scan failed
+          if [ "$use_inbuild" = "true" ] && { [ "$scan_success" != "true" ] || [ "$vuln_cnt" -eq 0 ]; }; then
+            echo "::warning::In-build SBOM for target image (${arch}) yielded ${vuln_cnt} CVE findings. Falling back to direct Trivy image scan..."
+            t_plat="linux/${arch}"
+            [ "$arch" = "default" ] && t_plat=""
+            plat_arg=""
+            [ -n "$t_plat" ] && plat_arg="--platform $t_plat"
+            if trivy image --skip-version-check $plat_arg --format spdx-json --output "$f" "${{ inputs.target-image }}"; then
+              echo "Re-scanning target SBOM generated directly by Trivy..."
+              if trivy sbom --skip-version-check --format json --output "$out_json" "$f" 2>"$err_log"; then
+                scan_success=true
+                if [ -s "$out_json" ]; then
+                  cnt=$(grep -c '"VulnerabilityID"' "$out_json" 2>/dev/null || true)
+                  cnt=$(echo "$cnt" | tr -d '[:space:]')
+                  [ -n "$cnt" ] && vuln_cnt="$cnt"
+                fi
+              fi
+            fi
+          fi
+
+          if [ "$scan_success" = "true" ]; then
+            if [ -s "$out_json" ]; then
+              if [ "$vuln_cnt" -eq 0 ]; then
+                echo "::warning::Target baseline image architecture '${arch}' has 0 CVE findings. Verify that OS/packages were recognized."
+                target_summary+=("  - ${arch}: ⚠️ WARNING (0 vulnerability findings detected)")
+              else
+                target_summary+=("  - ${arch}: ✅ OK (${vuln_cnt} vulnerability findings)")
+              fi
+              target_report_count=$((target_report_count + 1))
+            else
+              target_ok=false
+              target_summary+=("  - ${arch}: ❌ FAILED (Output report was empty / 0 bytes)")
+            fi
+          else
+            target_ok=false
+            err_msg=$(tail -n 2 "$err_log" | tr '\n' ' ' | sed 's/  */ /g')
+            [ -z "$err_msg" ] && err_msg="Trivy scan exited with non-zero status"
+            target_summary+=("  - ${arch}: ❌ FAILED (${err_msg})")
+          fi
+        done
+      fi
+
+      # 3. Print Comprehensive Diagnostic Overview
+      echo ""
+      echo "================================================================================"
+      echo "                   CVE VULNERABILITY SCAN DIAGNOSTIC OVERVIEW                  "
+      echo "================================================================================"
+      if [ "$use_inbuild" = "true" ]; then
+        echo "Scan Strategy: Built-in OCI Attestation (Syft/Docker Scout) with distro detection"
+      else
+        echo "Scan Strategy: Direct Trivy Image Scan (Full rootfs & source package mapping)"
+      fi
+      echo "--------------------------------------------------------------------------------"
+      echo "HEAD Image: ${{ inputs.head-image }}"
+      for line in "${head_summary[@]}"; do
+        echo "$line"
+      done
+      echo ""
+      echo "TARGET Baseline Image: ${{ inputs.target-image }} (branch: '${{ inputs.target-branch }}')"
+      for line in "${target_summary[@]}"; do
+        echo "$line"
+      done
+      echo "================================================================================"
+      echo ""
+
+      # 4. Enforce Gating: Both must have succeeded with valid reports
+      has_error=false
+      if [ "$head_ok" != "true" ] || [ "$head_report_count" -eq 0 ]; then
+        echo "::error::Head image CVE analysis failed or produced no reports."
+        has_error=true
+      fi
+
+      if [ "$target_ok" != "true" ] || [ "$target_report_count" -eq 0 ]; then
+        echo "::error::Target baseline CVE analysis failed or produced no reports."
+        has_error=true
+      fi
+
+      if [ "$has_error" = "true" ]; then
+        echo "::error::Aborting differential analysis: both head and target scans must succeed before diffing."
+        exit 1
+      fi
+
+      # 5. Run multi-arch set-based diff and generate consolidated full summary report
+      echo "Both head and target scans succeeded. Computing set-based vulnerability delta..."
+      if ! node "${{ github.action_path }}/cve-diff.js" \
+        "cve-reports/target" \
+        "cve-reports/head" \
+        "${{ inputs.target-branch }}" \
+        "${{ inputs.output-summary }}" > "${{ inputs.output-delta }}"; then
+        echo "::error::Failed to generate CVE differential report"
+        exit 1
+      fi
 
   - name: Publish Reports to Step Summary
     shell: bash
diff --git a/lib/diagnostics.js b/lib/diagnostics.js
deleted file mode 100644
index 75b4de3..0000000
--- a/lib/diagnostics.js
+++ /dev/null
@@ -1,106 +0,0 @@
-/**
- * Diagnostic formatting and reporting utilities.
- */
-
-function formatSbomOverview({
-  headImage,
-  targetImage,
-  headFiles = [],
-  targetFiles = [],
-  headError = null,
-  targetError = null,
-}) {
-  const lines = [
-    '',
-    '================================================================================',
-    '                      SBOM EXTRACTION DIAGNOSTIC OVERVIEW                       ',
-    '================================================================================',
-  ];
-
-  if (headError) {
-    lines.push(`HEAD Image (${headImage}): ❌ FAILED - ${headError}`);
-  } else {
-    lines.push(`HEAD Image (${headImage}): ✅ SUCCESS`);
-    for (const f of headFiles) {
-      lines.push(`  - ${f.name} (${f.size} bytes)`);
-    }
-  }
-
-  if (targetError) {
-    lines.push(`TARGET Baseline Image (${targetImage}): ❌ FAILED - ${targetError}`);
-  } else {
-    lines.push(`TARGET Baseline Image (${targetImage}): ✅ SUCCESS`);
-    for (const f of targetFiles) {
-      lines.push(`  - ${f.name} (${f.size} bytes)`);
-    }
-  }
-
-  lines.push('================================================================================');
-  lines.push('');
-  return lines.join('\n');
-}
-
-function formatScanOverview({
-  headImage,
-  targetImage,
-  targetBranch = 'main',
-  strategy = null,
-  headSummary = [],
-  targetSummary = [],
-}) {
-  const lines = [
-    '',
-    '================================================================================',
-    '                   CVE VULNERABILITY SCAN DIAGNOSTIC OVERVIEW                  ',
-    '================================================================================',
-  ];
-
-  if (strategy) {
-    lines.push(`Scan Strategy: ${strategy}`);
-    lines.push('--------------------------------------------------------------------------------');
-  }
-
-  lines.push(`HEAD Image: ${headImage}`);
-  for (const line of headSummary) {
-    lines.push(line);
-  }
-
-  lines.push('');
-  lines.push(`TARGET Baseline Image: ${targetImage} (branch: '${targetBranch}')`);
-  for (const line of targetSummary) {
-    lines.push(line);
-  }
-
-  lines.push('================================================================================');
-  lines.push('');
-  return lines.join('\n');
-}
-
-function countVulnerabilities(report) {
-  if (!report) return 0;
-  let data = report;
-  if (typeof report === 'string' || Buffer.isBuffer(report)) {
-    try {
-      data = JSON.parse(report.toString('utf8'));
-    } catch {
-      return 0;
-    }
-  }
-  if (!data || typeof data !== 'object') return 0;
-
-  let count = 0;
-  if (Array.isArray(data.Results)) {
-    for (const res of data.Results) {
-      if (res && Array.isArray(res.Vulnerabilities)) {
-        count += res.Vulnerabilities.length;
-      }
-    }
-  }
-  return count;
-}
-
-module.exports = {
-  formatSbomOverview,
-  formatScanOverview,
-  countVulnerabilities,
-};
diff --git a/lib/distro.js b/lib/distro.js
deleted file mode 100644
index 6b902a1..0000000
--- a/lib/distro.js
+++ /dev/null
@@ -1,42 +0,0 @@
-/**
- * Distribution detection from SPDX SBOM package PURLs.
- */
-
-function detectDistro(spdxInput) {
-  if (!spdxInput) return null;
-
-  let data = spdxInput;
-  if (typeof spdxInput === 'string' || Buffer.isBuffer(spdxInput)) {
-    try {
-      data = JSON.parse(spdxInput.toString('utf8'));
-    } catch {
-      return null;
-    }
-  }
-
-  if (!data || typeof data !== 'object' || !Array.isArray(data.packages)) {
-    return null;
-  }
-
-  for (const pkg of data.packages) {
-    if (!pkg || !Array.isArray(pkg.externalRefs)) continue;
-    for (const ref of pkg.externalRefs) {
-      if (ref && ref.referenceType === 'purl' && typeof ref.referenceLocator === 'string') {
-        const purl = ref.referenceLocator;
-        const nameMatch = purl.match(/[?&]os_name=([^&]+)/);
-        const verMatch = purl.match(/[?&]os_version=([^&]+)/);
-        if (nameMatch && verMatch) {
-          const osName = decodeURIComponent(nameMatch[1]);
-          const osVer = decodeURIComponent(verMatch[1]);
-          return `${osName}/${osVer}`;
-        }
-      }
-    }
-  }
-
-  return null;
-}
-
-module.exports = {
-  detectDistro,
-};
diff --git a/lib/extract-sboms.js b/lib/extract-sboms.js
deleted file mode 100644
index 7d0d5d1..0000000
--- a/lib/extract-sboms.js
+++ /dev/null
@@ -1,202 +0,0 @@
-#!/usr/bin/env node
-
-/**
- * Extracts or generates multi-platform SBOMs for head and target images.
- */
-
-const fs = require('node:fs');
-const path = require('node:path');
-const cp = require('node:child_process');
-const { parsePlatforms, discoverPlatforms, toArchTag } = require('./platforms.js');
-const { formatSbomOverview } = require('./diagnostics.js');
-
-function parseArgs(argv) {
-  const args = {
-    headImage: process.env.INPUT_HEAD_IMAGE || '',
-    targetImage: process.env.INPUT_TARGET_IMAGE || '',
-    architectures: process.env.INPUT_ARCHITECTURES || '',
-    useInbuildSbom: process.env.INPUT_USE_INBUILD_SBOM || 'false',
-  };
-
-  for (let i = 2; i < argv.length; i++) {
-    const arg = argv[i];
-    if (arg === '--head-image' && i + 1 < argv.length) args.headImage = argv[++i];
-    else if (arg === '--target-image' && i + 1 < argv.length) args.targetImage = argv[++i];
-    else if (arg === '--architectures' && i + 1 < argv.length) args.architectures = argv[++i];
-    else if (arg === '--use-inbuild-sbom' && i + 1 < argv.length) args.useInbuildSbom = argv[++i];
-  }
-
-  return args;
-}
-
-function cleanupInvalidFile(filePath) {
-  if (!fs.existsSync(filePath)) return;
-  try {
-    const stat = fs.statSync(filePath);
-    if (stat.size === 0) {
-      fs.unlinkSync(filePath);
-      return;
-    }
-    const content = fs.readFileSync(filePath, 'utf8').trim();
-    if (content === 'null' || content === '') {
-      fs.unlinkSync(filePath);
-    }
-  } catch {
-    // Ignore cleanup errors
-  }
-}
-
-function runCommandSafe(cmd, args) {
-  try {
-    return cp.execFileSync(cmd, args, { stdio: ['ignore', 'pipe', 'pipe'] }).toString('utf8');
-  } catch {
-    return null;
-  }
-}
-
-function extractOrGenerateSbom({ image, platform, archTag, outputDir, useInbuild }) {
-  const outputFile = path.join(outputDir, `sbom-${archTag}.spdx.json`);
-  const inbuildFile = path.join(outputDir, `inbuild-sbom-${archTag}.spdx.json`);
-
-  // 1. Attempt in-build SBOM extraction if requested
-  if (useInbuild) {
-    console.log(`Attempting extraction of built-in SBOM for image (${platform})...`);
-    const formatStr = `{{ json (index .SBOM "${platform}").SPDX }}`;
-    const rawSbom = runCommandSafe('docker', ['buildx', 'imagetools', 'inspect', image, '--format', formatStr]);
-    if (rawSbom) {
-      fs.writeFileSync(outputFile, rawSbom);
-      cleanupInvalidFile(outputFile);
-      if (fs.existsSync(outputFile)) {
-        fs.copyFileSync(outputFile, inbuildFile);
-      }
-    }
-  }
-
-  // 2. Fallback to direct Trivy image generation if SBOM not present
-  if (!fs.existsSync(outputFile)) {
-    console.log(`Generating SBOM for image (${platform}) with Trivy...`);
-    const platArgs = platform ? ['--platform', platform] : [];
-    try {
-      cp.execFileSync('trivy', [
-        'image',
-        '--skip-version-check',
-        ...platArgs,
-        '--format', 'spdx-json',
-        '--output', outputFile,
-        image,
-      ], { stdio: 'inherit' });
-    } catch (e) {
-      console.warn(`::warning::Trivy image scan failed for image (${platform}): ${e.message}`);
-    }
-    cleanupInvalidFile(outputFile);
-  }
-}
-
-function main() {
-  const args = parseArgs(process.argv);
-  const { headImage, targetImage, architectures, useInbuildSbom } = args;
-  const useInbuild = useInbuildSbom === 'true';
-
-  if (!headImage || !targetImage) {
-    console.error('::error::Both --head-image and --target-image must be provided.');
-    process.exit(1);
-  }
-
-  const headDir = path.join('sboms', 'head');
-  const targetDir = path.join('sboms', 'target');
-  fs.mkdirSync(headDir, { recursive: true });
-  fs.mkdirSync(targetDir, { recursive: true });
-
-  // Determine platforms
-  let platforms = parsePlatforms(architectures);
-  if (platforms.length === 0) {
-    console.log('Auto-discovering architectures from images...');
-    const rawHead = runCommandSafe('docker', ['buildx', 'imagetools', 'inspect', '--raw', headImage]);
-    const rawTarget = runCommandSafe('docker', ['buildx', 'imagetools', 'inspect', '--raw', targetImage]);
-    platforms = discoverPlatforms(rawHead, rawTarget);
-  }
-
-  console.log(`Configured platforms: ${platforms.length > 0 ? platforms.join(', ') : '(single platform fallback)'}`);
-  if (useInbuild) {
-    console.log('ℹ️  Strategy: Built-in SBOM attestation extraction enabled (Docker Scout / Syft). Skips container layer downloads for maximum speed.');
-    console.log('ℹ️  Note: Built-in SBOM vulnerability counts may differ from direct filesystem scans (\'trivy image\') due to binary vs. source package tracking.');
-  } else {
-    console.log('ℹ️  Strategy: Direct Trivy image scanning enabled (default). Inspects full container rootfs and package databases for maximum fidelity.');
-  }
-
-  const targetPlatforms = platforms.length > 0 ? platforms : [''];
-
-  for (const platform of targetPlatforms) {
-    const archTag = toArchTag(platform);
-    // Head extraction
-    extractOrGenerateSbom({
-      image: headImage,
-      platform,
-      archTag,
-      outputDir: headDir,
-      useInbuild,
-    });
-    // Target extraction
-    extractOrGenerateSbom({
-      image: targetImage,
-      platform,
-      archTag,
-      outputDir: targetDir,
-      useInbuild,
-    });
-  }
-
-  // Collect generated files
-  const getSbomFiles = (dir) => {
-    if (!fs.existsSync(dir)) return [];
-    return fs.readdirSync(dir)
-      .filter((f) => f.startsWith('sbom-') && f.endsWith('.spdx.json'))
-      .map((f) => {
-        const fullPath = path.join(dir, f);
-        return { name: f, size: fs.statSync(fullPath).size };
-      });
-  };
-
-  const headFiles = getSbomFiles(headDir);
-  const targetFiles = getSbomFiles(targetDir);
-
-  let headError = null;
-  let targetError = null;
-  if (headFiles.length === 0) headError = 'No SBOM generated and head image could not be inspected';
-  if (targetFiles.length === 0) targetError = 'No SBOM generated and target baseline image could not be inspected';
-
-  const overview = formatSbomOverview({
-    headImage,
-    targetImage,
-    headFiles,
-    targetFiles,
-    headError,
-    targetError,
-  });
-  console.log(overview);
-
-  if (headError || targetError) {
-    console.error('::error::Both head and target images must have valid SBOMs to proceed with differential scanning.');
-    process.exit(1);
-  }
-
-  // Expose extracted head SBOMs to workspace root for workflow artifact uploads
-  for (const file of headFiles) {
-    try {
-      fs.copyFileSync(path.join(headDir, file.name), file.name);
-    } catch {
-      // Ignore copy error
-    }
-  }
-}
-
-if (require.main === module) {
-  main();
-}
-
-module.exports = {
-  parseArgs,
-  cleanupInvalidFile,
-  extractOrGenerateSbom,
-  main,
-};
diff --git a/lib/install-trivy.js b/lib/install-trivy.js
deleted file mode 100644
index e3b06aa..0000000
--- a/lib/install-trivy.js
+++ /dev/null
@@ -1,75 +0,0 @@
-#!/usr/bin/env node
-
-/**
- * Installs and verifies Trivy binary against checksums lockfile.
- */
-
-const fs = require('node:fs');
-const path = require('node:path');
-const os = require('node:os');
-const cp = require('node:child_process');
-const { mapArch, parseChecksums, verifyFileSha256 } = require('./verifier.js');
-
-function main() {
-  const version = process.env.TRIVY_VERSION || '0.74.0';
-  const homeDir = os.homedir();
-  const binDir = path.join(homeDir, '.local', 'bin');
-  const cacheDir = path.join(homeDir, '.cache', 'trivy-bin');
-
-  fs.mkdirSync(binDir, { recursive: true });
-  fs.mkdirSync(cacheDir, { recursive: true });
-
-  // Expose bin directory to GITHUB_PATH if running in Actions runner
-  if (process.env.GITHUB_PATH) {
-    fs.appendFileSync(process.env.GITHUB_PATH, `${binDir}\n`);
-  }
-
-  const unameArch = os.arch() === 'x64' ? 'x86_64' : (os.arch() === 'arm64' ? 'ARM64' : os.arch());
-  const tArch = mapArch(unameArch);
-  const tarball = `trivy_${version}_Linux-${tArch}.tar.gz`;
-  const tarballPath = path.join(cacheDir, tarball);
-
-  const checksumsFile = path.resolve(__dirname, '..', 'checksums.txt');
-  if (!fs.existsSync(checksumsFile)) {
-    console.error(`::error::Checksums lockfile not found at ${checksumsFile}`);
-    process.exit(1);
-  }
-
-  const checksums = parseChecksums(fs.readFileSync(checksumsFile, 'utf8'));
-  const expectedHash = checksums.get(tarball);
-  if (!expectedHash) {
-    console.error(`::error::Tarball ${tarball} not found in checksums.txt`);
-    process.exit(1);
-  }
-
-  if (fs.existsSync(tarballPath) && verifyFileSha256(tarballPath, expectedHash)) {
-    console.log('Cached Trivy archive verified against lockfile.');
-  } else {
-    console.log('Archive missing or checksum mismatch; downloading...');
-    const downloadUrl = `https://github.com/aquasecurity/trivy/releases/download/v${version}/${tarball}`;
-    cp.execFileSync('curl', ['-sfLO', downloadUrl, '--output-dir', cacheDir], { stdio: 'inherit' });
-
-    if (!verifyFileSha256(tarballPath, expectedHash)) {
-      console.error(`::error::Downloaded archive ${tarball} failed SHA256 checksum verification!`);
-      process.exit(1);
-    }
-    console.log('Downloaded Trivy archive verified successfully.');
-  }
-
-  // Extract binary
-  cp.execFileSync('tar', ['-xzf', tarballPath, '-C', binDir, 'trivy'], { stdio: 'inherit' });
-  const trivyBin = path.join(binDir, 'trivy');
-  if (fs.existsSync(trivyBin)) {
-    fs.chmodSync(trivyBin, 0o755);
-    console.log(`Trivy ${version} installed and verified successfully at ${trivyBin}`);
-  } else {
-    console.error('::error::Failed to extract trivy binary from tarball.');
-    process.exit(1);
-  }
-}
-
-if (require.main === module) {
-  main();
-}
-
-module.exports = { main };
diff --git a/lib/platforms.js b/lib/platforms.js
deleted file mode 100644
index 2465df9..0000000
--- a/lib/platforms.js
+++ /dev/null
@@ -1,54 +0,0 @@
-/**
- * Platform and architecture resolution utilities.
- */
-
-function parsePlatforms(input) {
-  if (!input || typeof input !== 'string') return [];
-  const parts = input.split(',');
-  const platforms = [];
-  for (const part of parts) {
-    const clean = part.trim();
-    if (!clean) continue;
-    if (!clean.includes('/')) {
-      platforms.push(`linux/${clean}`);
-    } else {
-      platforms.push(clean);
-    }
-  }
-  return platforms;
-}
-
-function discoverPlatforms(headRawJson, targetRawJson) {
-  const set = new Set();
-  for (const raw of [headRawJson, targetRawJson]) {
-    if (!raw) continue;
-    try {
-      const data = JSON.parse(raw);
-      const manifests = data.manifests || [];
-      for (const m of manifests) {
-        if (m.platform && m.platform.architecture && m.platform.architecture !== 'unknown') {
-          const os = m.platform.os || 'linux';
-          const variant = m.platform.variant ? `/${m.platform.variant}` : '';
-          set.add(`${os}/${m.platform.architecture}${variant}`);
-        }
-      }
-    } catch {
-      // Ignore JSON parse errors from invalid manifests
-    }
-  }
-  return Array.from(set).sort();
-}
-
-function toArchTag(platform) {
-  if (!platform) return 'default';
-  // Strip optional leading os/ (e.g. linux/)
-  const withoutOs = platform.replace(/^[a-zA-Z0-9_-]+\//, '');
-  // Replace slashes with dashes (e.g. arm/v7 -> arm-v7)
-  return withoutOs.replace(/\//g, '-');
-}
-
-module.exports = {
-  parsePlatforms,
-  discoverPlatforms,
-  toArchTag,
-};
diff --git a/lib/scan-sboms.js b/lib/scan-sboms.js
deleted file mode 100644
index 2e4547c..0000000
--- a/lib/scan-sboms.js
+++ /dev/null
@@ -1,280 +0,0 @@
-#!/usr/bin/env node
-
-/**
- * Scans multi-platform SBOMs with Trivy, handles distro detection and fallbacks,
- * prints diagnostic overview, and invokes diff engine.
- */
-
-const fs = require('node:fs');
-const path = require('node:path');
-const cp = require('node:child_process');
-const { detectDistro } = require('./distro.js');
-const { formatScanOverview, countVulnerabilities } = require('./diagnostics.js');
-
-function parseArgs(argv) {
-  const args = {
-    headImage: process.env.INPUT_HEAD_IMAGE || '',
-    targetImage: process.env.INPUT_TARGET_IMAGE || '',
-    targetBranch: process.env.INPUT_TARGET_BRANCH || 'main',
-    useInbuildSbom: process.env.INPUT_USE_INBUILD_SBOM || 'false',
-    outputDelta: process.env.INPUT_OUTPUT_DELTA || 'cve-delta.md',
-    outputSummary: process.env.INPUT_OUTPUT_SUMMARY || 'cve-summary.md',
-  };
-
-  for (let i = 2; i < argv.length; i++) {
-    const arg = argv[i];
-    if (arg === '--head-image' && i + 1 < argv.length) args.headImage = argv[++i];
-    else if (arg === '--target-image' && i + 1 < argv.length) args.targetImage = argv[++i];
-    else if (arg === '--target-branch' && i + 1 < argv.length) args.targetBranch = argv[++i];
-    else if (arg === '--use-inbuild-sbom' && i + 1 < argv.length) args.useInbuildSbom = argv[++i];
-    else if (arg === '--output-delta' && i + 1 < argv.length) args.outputDelta = argv[++i];
-    else if (arg === '--output-summary' && i + 1 < argv.length) args.outputSummary = argv[++i];
-  }
-
-  return args;
-}
-
-function scanSbomFile({ sbomPath, image, outJson, errLog, useInbuild }) {
-  const archMatch = path.basename(sbomPath, '.spdx.json').match(/^sbom-(.+)$/);
-  const arch = archMatch ? archMatch[1] : 'default';
-
-  console.log(`Scanning SBOM for architecture: ${arch}`);
-  let distroArg = [];
-  if (useInbuild) {
-    try {
-      const content = fs.readFileSync(sbomPath, 'utf8');
-      const detected = detectDistro(content);
-      if (detected) {
-        console.log(`Detected distribution '${detected}' from in-build SBOM PURLs. Scanning with --distro.`);
-        distroArg = ['--distro', detected];
-      }
-    } catch {
-      // Ignore read error
-    }
-  }
-
-  const runTrivySbom = () => {
-    try {
-      const errFd = fs.openSync(errLog, 'w');
-      try {
-        cp.execFileSync('trivy', [
-          'sbom',
-          ...distroArg,
-          '--skip-version-check',
-          '--format', 'json',
-          '--output', outJson,
-          sbomPath,
-        ], { stdio: ['ignore', 'ignore', errFd] });
-        return true;
-      } finally {
-        fs.closeSync(errFd);
-      }
-    } catch {
-      return false;
-    }
-  };
-
-  let scanSuccess = runTrivySbom();
-  let vulnCount = 0;
-  if (fs.existsSync(outJson) && fs.statSync(outJson).size > 0) {
-    vulnCount = countVulnerabilities(fs.readFileSync(outJson, 'utf8'));
-  }
-
-  // Fallback if in-build scan produced 0 findings or failed
-  if (useInbuild && (!scanSuccess || vulnCount === 0)) {
-    console.warn(`::warning::In-build SBOM for image (${arch}) yielded ${vulnCount} CVE findings. Falling back to direct Trivy image scan...`);
-    const platArgs = arch !== 'default' ? ['--platform', `linux/${arch}`] : [];
-    try {
-      cp.execFileSync('trivy', [
-        'image',
-        '--skip-version-check',
-        ...platArgs,
-        '--format', 'spdx-json',
-        '--output', sbomPath,
-        image,
-      ], { stdio: 'inherit' });
-
-      console.log('Re-scanning SBOM generated directly by Trivy...');
-      // Re-scan without external distroArg (Trivy's generated SBOM has OS declarations)
-      distroArg = [];
-      scanSuccess = runTrivySbom();
-      if (fs.existsSync(outJson) && fs.statSync(outJson).size > 0) {
-        vulnCount = countVulnerabilities(fs.readFileSync(outJson, 'utf8'));
-      }
-    } catch (e) {
-      console.warn(`::warning::Direct Trivy scan fallback failed for ${arch}: ${e.message}`);
-    }
-  }
-
-  return { arch, scanSuccess, vulnCount, outJson, errLog };
-}
-
-function main() {
-  const args = parseArgs(process.argv);
-  const {
-    headImage,
-    targetImage,
-    targetBranch,
-    useInbuildSbom,
-    outputDelta,
-    outputSummary,
-  } = args;
-  const useInbuild = useInbuildSbom === 'true';
-
-  fs.mkdirSync(path.join('cve-reports', 'head'), { recursive: true });
-  fs.mkdirSync(path.join('cve-reports', 'target'), { recursive: true });
-
-  const getSboms = (dir) => {
-    if (!fs.existsSync(dir)) return [];
-    return fs.readdirSync(dir)
-      .filter((f) => f.startsWith('sbom-') && f.endsWith('.spdx.json'))
-      .sort()
-      .map((f) => path.join(dir, f));
-  };
-
-  const headSboms = getSboms(path.join('sboms', 'head'));
-  const targetSboms = getSboms(path.join('sboms', 'target'));
-
-  let headOk = true;
-  let targetOk = true;
-  let headReportCount = 0;
-  let targetReportCount = 0;
-  const headSummary = [];
-  const targetSummary = [];
-
-  // 1. Scan Head SBOMs
-  if (headSboms.length === 0) {
-    headOk = false;
-    headSummary.push('  - ❌ No SBOM files found in sboms/head/');
-  } else {
-    for (const f of headSboms) {
-      const arch = path.basename(f, '.spdx.json').replace(/^sbom-/, '');
-      const outJson = path.join('cve-reports', 'head', `cve-${arch}.json`);
-      const errLog = path.join('cve-reports', 'head', `cve-${arch}.err`);
-
-      const res = scanSbomFile({
-        sbomPath: f,
-        image: headImage,
-        outJson,
-        errLog,
-        useInbuild,
-      });
-
-      if (res.scanSuccess && fs.existsSync(outJson) && fs.statSync(outJson).size > 0) {
-        if (res.vulnCount === 0) {
-          console.warn(`::warning::Head image architecture '${arch}' has 0 CVE findings. Verify that OS/packages were recognized.`);
-          headSummary.push(`  - ${arch}: ⚠️ WARNING (0 vulnerability findings detected)`);
-        } else {
-          headSummary.push(`  - ${arch}: ✅ OK (${res.vulnCount} vulnerability findings)`);
-        }
-        headReportCount++;
-      } else {
-        headOk = false;
-        let errMsg = 'Trivy scan exited with non-zero status';
-        if (fs.existsSync(errLog)) {
-          const errLines = fs.readFileSync(errLog, 'utf8').trim().split('\n');
-          errMsg = errLines.slice(-2).join(' ').replace(/\s+/g, ' ') || errMsg;
-        }
-        headSummary.push(`  - ${arch}: ❌ FAILED (${errMsg})`);
-      }
-    }
-  }
-
-  // 2. Scan Target SBOMs
-  if (targetSboms.length === 0) {
-    targetOk = false;
-    targetSummary.push('  - ❌ No SBOM files found in sboms/target/');
-  } else {
-    for (const f of targetSboms) {
-      const arch = path.basename(f, '.spdx.json').replace(/^sbom-/, '');
-      const outJson = path.join('cve-reports', 'target', `cve-${arch}.json`);
-      const errLog = path.join('cve-reports', 'target', `cve-${arch}.err`);
-
-      const res = scanSbomFile({
-        sbomPath: f,
-        image: targetImage,
-        outJson,
-        errLog,
-        useInbuild,
-      });
-
-      if (res.scanSuccess && fs.existsSync(outJson) && fs.statSync(outJson).size > 0) {
-        if (res.vulnCount === 0) {
-          console.warn(`::warning::Target baseline image architecture '${arch}' has 0 CVE findings. Verify that OS/packages were recognized.`);
-          targetSummary.push(`  - ${arch}: ⚠️ WARNING (0 vulnerability findings detected)`);
-        } else {
-          targetSummary.push(`  - ${arch}: ✅ OK (${res.vulnCount} vulnerability findings)`);
-        }
-        targetReportCount++;
-      } else {
-        targetOk = false;
-        let errMsg = 'Trivy scan exited with non-zero status';
-        if (fs.existsSync(errLog)) {
-          const errLines = fs.readFileSync(errLog, 'utf8').trim().split('\n');
-          errMsg = errLines.slice(-2).join(' ').replace(/\s+/g, ' ') || errMsg;
-        }
-        targetSummary.push(`  - ${arch}: ❌ FAILED (${errMsg})`);
-      }
-    }
-  }
-
-  // 3. Print Comprehensive Diagnostic Overview
-  const strategy = useInbuild
-    ? 'Built-in OCI Attestation (Syft/Docker Scout) with distro detection'
-    : 'Direct Trivy Image Scan (Full rootfs & source package mapping)';
-
-  const overview = formatScanOverview({
-    headImage,
-    targetImage,
-    targetBranch,
-    strategy,
-    headSummary,
-    targetSummary,
-  });
-  console.log(overview);
-
-  // 4. Enforce Gating
-  let hasError = false;
-  if (!headOk || headReportCount === 0) {
-    console.error('::error::Head image CVE analysis failed or produced no reports.');
-    hasError = true;
-  }
-  if (!targetOk || targetReportCount === 0) {
-    console.error('::error::Target baseline CVE analysis failed or produced no reports.');
-    hasError = true;
-  }
-
-  if (hasError) {
-    console.error('::error::Aborting differential analysis: both head and target scans must succeed before diffing.');
-    process.exit(1);
-  }
-
-  // 5. Run multi-arch set-based diff and generate reports
-  console.log('Both head and target scans succeeded. Computing set-based vulnerability delta...');
-  const cveDiffScript = path.resolve(__dirname, '..', 'cve-diff.js');
-  try {
-    const deltaOutput = cp.execFileSync(process.execPath, [
-      cveDiffScript,
-      path.join('cve-reports', 'target'),
-      path.join('cve-reports', 'head'),
-      targetBranch,
-      outputSummary,
-    ], { encoding: 'utf8' });
-
-    fs.writeFileSync(outputDelta, deltaOutput, 'utf8');
-    console.log(`CVE delta written to ${outputDelta} and full summary written to ${outputSummary}`);
-  } catch (e) {
-    console.error(`::error::Failed to generate CVE differential report: ${e.message}`);
-    process.exit(1);
-  }
-}
-
-if (require.main === module) {
-  main();
-}
-
-module.exports = {
-  parseArgs,
-  scanSbomFile,
-  main,
-};
diff --git a/lib/verifier.js b/lib/verifier.js
deleted file mode 100644
index d3182d4..0000000
--- a/lib/verifier.js
+++ /dev/null
@@ -1,56 +0,0 @@
-/**
- * Architecture mapping and cryptographic checksum verification.
- */
-
-const fs = require('node:fs');
-const crypto = require('node:crypto');
-
-function mapArch(unameArch) {
-  const normalized = (unameArch || '').trim().toLowerCase();
-  switch (normalized) {
-    case 'x86_64':
-    case 'amd64':
-      return '64bit';
-    case 'aarch64':
-    case 'arm64':
-      return 'ARM64';
-    default:
-      throw new Error(`Unsupported architecture: ${unameArch}`);
-  }
-}
-
-function parseChecksums(checksumsContent) {
-  const map = new Map();
-  if (!checksumsContent) return map;
-
-  const lines = checksumsContent.split(/\r?\n/);
-  for (const line of lines) {
-    const trimmed = line.trim();
-    if (!trimmed || trimmed.startsWith('#')) continue;
-    // Format: <hash>  <filename>
-    const match = trimmed.match(/^([a-fA-F0-9]{64})\s+(.+)$/);
-    if (match) {
-      const hash = match[1].toLowerCase();
-      const filename = match[2].trim();
-      map.set(filename, hash);
-    }
-  }
-  return map;
-}
-
-function verifyFileSha256(filePath, expectedHash) {
-  if (!fs.existsSync(filePath) || !expectedHash) return false;
-  try {
-    const fileBuffer = fs.readFileSync(filePath);
-    const actualHash = crypto.createHash('sha256').update(fileBuffer).digest('hex');
-    return actualHash.toLowerCase() === expectedHash.toLowerCase();
-  } catch {
-    return false;
-  }
-}
-
-module.exports = {
-  mapArch,
-  parseChecksums,
-  verifyFileSha256,
-};
diff --git a/test/diagnostics.test.js b/test/diagnostics.test.js
deleted file mode 100644
index b8a97e4..0000000
--- a/test/diagnostics.test.js
+++ /dev/null
@@ -1,76 +0,0 @@
-const test = require('node:test');
-const assert = require('node:assert/strict');
-const {
-  formatSbomOverview,
-  formatScanOverview,
-  countVulnerabilities,
-} = require('../lib/diagnostics.js');
-
-test('formatSbomOverview formats successful extraction banner', () => {
-  const overview = formatSbomOverview({
-    headImage: 'my-head:latest',
-    targetImage: 'my-target:latest',
-    headFiles: [{ name: 'sbom-amd64.spdx.json', size: 1024 }],
-    targetFiles: [{ name: 'sbom-amd64.spdx.json', size: 2048 }],
-    headError: null,
-    targetError: null,
-  });
-
-  assert.ok(overview.includes('SBOM EXTRACTION DIAGNOSTIC OVERVIEW'));
-  assert.ok(overview.includes('HEAD Image (my-head:latest): ✅ SUCCESS'));
-  assert.ok(overview.includes('TARGET Baseline Image (my-target:latest): ✅ SUCCESS'));
-  assert.ok(overview.includes('sbom-amd64.spdx.json (1024 bytes)'));
-});
-
-test('formatSbomOverview formats failure banner when error present', () => {
-  const overview = formatSbomOverview({
-    headImage: 'my-head:latest',
-    targetImage: 'my-target:latest',
-    headFiles: [],
-    targetFiles: [],
-    headError: 'Image not found',
-    targetError: null,
-  });
-
-  assert.ok(overview.includes('HEAD Image (my-head:latest): ❌ FAILED - Image not found'));
-});
-
-test('formatScanOverview formats scan summary with strategy', () => {
-  const overview = formatScanOverview({
-    headImage: 'debian:bookworm-slim',
-    targetImage: 'debian:bullseye-slim',
-    targetBranch: 'main',
-    strategy: 'Direct Trivy Image Scan',
-    headSummary: ['  - amd64: ✅ OK (104 vulnerability findings)'],
-    targetSummary: ['  - amd64: ✅ OK (130 vulnerability findings)'],
-  });
-
-  assert.ok(overview.includes('CVE VULNERABILITY SCAN DIAGNOSTIC OVERVIEW'));
-  assert.ok(overview.includes('Scan Strategy: Direct Trivy Image Scan'));
-  assert.ok(overview.includes('HEAD Image: debian:bookworm-slim'));
-  assert.ok(overview.includes('TARGET Baseline Image: debian:bullseye-slim (branch: \'main\')'));
-  assert.ok(overview.includes('104 vulnerability findings'));
-});
-
-test('countVulnerabilities counts all vulnerabilities in a Trivy JSON report', () => {
-  const report = {
-    Results: [
-      {
-        Vulnerabilities: [
-          { VulnerabilityID: 'CVE-2023-0001' },
-          { VulnerabilityID: 'CVE-2023-0002' },
-        ],
-      },
-      {
-        Vulnerabilities: [
-          { VulnerabilityID: 'CVE-2023-0003' },
-        ],
-      },
-    ],
-  };
-
-  assert.equal(countVulnerabilities(report), 3);
-  assert.equal(countVulnerabilities(JSON.stringify(report)), 3);
-  assert.equal(countVulnerabilities({}), 0);
-  assert.equal(countVulnerabilities(null), 0);
-});
diff --git a/test/distro.test.js b/test/distro.test.js
deleted file mode 100644
index bd7952b..0000000
--- a/test/distro.test.js
+++ /dev/null
@@ -1,81 +0,0 @@
-const test = require('node:test');
-const assert = require('node:assert/strict');
-const { detectDistro } = require('../lib/distro.js');
-
-test('detectDistro returns null for null, undefined, or empty input', () => {
-  assert.equal(detectDistro(null), null);
-  assert.equal(detectDistro(undefined), null);
-  assert.equal(detectDistro(''), null);
-  assert.equal(detectDistro('{}'), null);
-});
-
-test('detectDistro extracts distro from parsed SPDX object with package PURLs', () => {
-  const spdx = {
-    packages: [
-      {
-        name: 'acl',
-        externalRefs: [
-          {
-            referenceType: 'purl',
-            referenceLocator: 'pkg:deb/debian/acl@2.3.1-3?os_distro=bookworm&os_name=debian&os_version=12',
-          },
-        ],
-      },
-    ],
-  };
-
-  assert.equal(detectDistro(spdx), 'debian/12');
-});
-
-test('detectDistro extracts distro from JSON string containing escaped unicode \\u0026', () => {
-  const jsonStr = JSON.stringify({
-    packages: [
-      {
-        name: 'adduser',
-        externalRefs: [
-          {
-            referenceType: 'purl',
-            referenceLocator: 'pkg:deb/debian/adduser@3.134?os_distro=bullseye&os_name=debian&os_version=11',
-          },
-        ],
-      },
-    ],
-  }).replace(/&/g, '\\u0026');
-
-  assert.ok(jsonStr.includes('\\u0026'));
-  assert.equal(detectDistro(jsonStr), 'debian/11');
-});
-
-test('detectDistro handles non-debian distributions (e.g. ubuntu, alpine)', () => {
-  const spdx = {
-    packages: [
-      {
-        externalRefs: [
-          {
-            referenceType: 'purl',
-            referenceLocator: 'pkg:apk/alpine/alpine-baselayout@3.4.3-r2?os_name=alpine&os_version=3.20',
-          },
-        ],
-      },
-    ],
-  };
-
-  assert.equal(detectDistro(spdx), 'alpine/3.20');
-});
-
-test('detectDistro returns null when PURLs lack os_name or os_version', () => {
-  const spdx = {
-    packages: [
-      {
-        externalRefs: [
-          {
-            referenceType: 'purl',
-            referenceLocator: 'pkg:generic/foo@1.0.0',
-          },
-        ],
-      },
-    ],
-  };
-
-  assert.equal(detectDistro(spdx), null);
-});
diff --git a/test/orchestration.test.js b/test/orchestration.test.js
deleted file mode 100644
index 10668b0..0000000
--- a/test/orchestration.test.js
+++ /dev/null
@@ -1,65 +0,0 @@
-const test = require('node:test');
-const assert = require('node:assert/strict');
-const fs = require('node:fs');
-const path = require('node:path');
-const os = require('node:os');
-const { parseArgs: parseExtractArgs, cleanupInvalidFile } = require('../lib/extract-sboms.js');
-const { parseArgs: parseScanArgs } = require('../lib/scan-sboms.js');
-
-test('extract-sboms parseArgs parses command line arguments and defaults', () => {
-  const argv = [
-    'node',
-    'extract-sboms.js',
-    '--head-image', 'my-repo/head:1.0',
-    '--target-image', 'my-repo/target:1.0',
-    '--architectures', 'amd64,arm64',
-    '--use-inbuild-sbom', 'true',
-  ];
-
-  const args = parseExtractArgs(argv);
-  assert.equal(args.headImage, 'my-repo/head:1.0');
-  assert.equal(args.targetImage, 'my-repo/target:1.0');
-  assert.equal(args.architectures, 'amd64,arm64');
-  assert.equal(args.useInbuildSbom, 'true');
-});
-
-test('extract-sboms cleanupInvalidFile removes empty files and files containing null', () => {
-  const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'sbom-clean-'));
-  const emptyFile = path.join(tmpDir, 'empty.json');
-  const nullFile = path.join(tmpDir, 'null.json');
-  const validFile = path.join(tmpDir, 'valid.json');
-
-  fs.writeFileSync(emptyFile, '');
-  fs.writeFileSync(nullFile, 'null\n');
-  fs.writeFileSync(validFile, '{"spdxVersion": "SPDX-2.3"}');
-
-  cleanupInvalidFile(emptyFile);
-  cleanupInvalidFile(nullFile);
-  cleanupInvalidFile(validFile);
-
-  assert.equal(fs.existsSync(emptyFile), false);
-  assert.equal(fs.existsSync(nullFile), false);
-  assert.equal(fs.existsSync(validFile), true);
-
-  fs.rmSync(tmpDir, { recursive: true, force: true });
-});
-
-test('scan-sboms parseArgs parses scan arguments and defaults', () => {
-  const argv = [
-    'node',
-    'scan-sboms.js',
-    '--head-image', 'my-head:latest',
-    '--target-image', 'my-target:latest',
-    '--target-branch', 'feature',
-    '--output-delta', 'custom-delta.md',
-    '--output-summary', 'custom-summary.md',
-  ];
-
-  const args = parseScanArgs(argv);
-  assert.equal(args.headImage, 'my-head:latest');
-  assert.equal(args.targetImage, 'my-target:latest');
-  assert.equal(args.targetBranch, 'feature');
-  assert.equal(args.outputDelta, 'custom-delta.md');
-  assert.equal(args.outputSummary, 'custom-summary.md');
-  assert.equal(args.useInbuildSbom, 'false');
-});
diff --git a/test/platforms.test.js b/test/platforms.test.js
deleted file mode 100644
index ead5bce..0000000
--- a/test/platforms.test.js
+++ /dev/null
@@ -1,47 +0,0 @@
-const test = require('node:test');
-const assert = require('node:assert/strict');
-const { parsePlatforms, discoverPlatforms, toArchTag } = require('../lib/platforms.js');
-
-test('parsePlatforms handles empty and undefined input', () => {
-  assert.deepEqual(parsePlatforms(''), []);
-  assert.deepEqual(parsePlatforms(null), []);
-  assert.deepEqual(parsePlatforms(undefined), []);
-  assert.deepEqual(parsePlatforms('   '), []);
-});
-
-test('parsePlatforms parses comma-separated architectures and adds linux/ prefix if omitted', () => {
-  const result = parsePlatforms('amd64, arm64, linux/arm/v7');
-  assert.deepEqual(result, ['linux/amd64', 'linux/arm64', 'linux/arm/v7']);
-});
-
-test('discoverPlatforms extracts unique architectures from OCI image manifests', () => {
-  const headManifest = JSON.stringify({
-    manifests: [
-      { platform: { architecture: 'amd64', os: 'linux' } },
-      { platform: { architecture: 'arm64', os: 'linux' } },
-      { platform: { architecture: 'unknown', os: 'unknown' } },
-    ],
-  });
-
-  const targetManifest = JSON.stringify({
-    manifests: [
-      { platform: { architecture: 'amd64', os: 'linux' } },
-      { platform: { architecture: 'arm', os: 'linux', variant: 'v7' } },
-    ],
-  });
-
-  const result = discoverPlatforms(headManifest, targetManifest);
-  assert.deepEqual(result, ['linux/amd64', 'linux/arm/v7', 'linux/arm64']);
-});
-
-test('discoverPlatforms safely handles invalid or missing manifest JSON', () => {
-  assert.deepEqual(discoverPlatforms('invalid json', null), []);
-  assert.deepEqual(discoverPlatforms('', '{}'), []);
-});
-
-test('toArchTag converts platform strings to filesystem-safe arch tags', () => {
-  assert.equal(toArchTag('linux/amd64'), 'amd64');
-  assert.equal(toArchTag('linux/arm64'), 'arm64');
-  assert.equal(toArchTag('linux/arm/v7'), 'arm-v7');
-  assert.equal(toArchTag('amd64'), 'amd64');
-});
diff --git a/test/verifier.test.js b/test/verifier.test.js
deleted file mode 100644
index 1bccc1e..0000000
--- a/test/verifier.test.js
+++ /dev/null
@@ -1,39 +0,0 @@
-const test = require('node:test');
-const assert = require('node:assert/strict');
-const fs = require('node:fs');
-const path = require('node:path');
-const os = require('node:os');
-const crypto = require('node:crypto');
-const { mapArch, parseChecksums, verifyFileSha256 } = require('../lib/verifier.js');
-
-test('mapArch maps uname architecture to Trivy release arch', () => {
-  assert.equal(mapArch('x86_64'), '64bit');
-  assert.equal(mapArch('aarch64'), 'ARM64');
-  assert.equal(mapArch('arm64'), 'ARM64');
-  assert.throws(() => mapArch('mips'), /Unsupported architecture/);
-});
-
-test('parseChecksums parses sha256 checksum lockfile into filename map', () => {
-  const content = `
-    e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855  trivy_0.74.0_Linux-64bit.tar.gz
-    a1b2c3d4e5f60000000000000000000000000000000000000000000000000000  trivy_0.74.0_Linux-ARM64.tar.gz
-  `;
-
-  const map = parseChecksums(content);
-  assert.equal(map.get('trivy_0.74.0_Linux-64bit.tar.gz'), 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855');
-  assert.equal(map.get('trivy_0.74.0_Linux-ARM64.tar.gz'), 'a1b2c3d4e5f60000000000000000000000000000000000000000000000000000');
-  assert.equal(map.has('nonexistent'), false);
-});
-
-test('verifyFileSha256 verifies actual sha256 hash of a file', () => {
-  const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cve-test-'));
-  const testFile = path.join(tmpDir, 'test.txt');
-  const fileContent = 'hello world\n';
-  fs.writeFileSync(testFile, fileContent);
-
-  const expectedHash = crypto.createHash('sha256').update(fileContent).digest('hex');
-  assert.equal(verifyFileSha256(testFile, expectedHash), true);
-  assert.equal(verifyFileSha256(testFile, 'wronghash'), false);
-
-  fs.rmSync(tmpDir, { recursive: true, force: true });
-});