feat: integrate npx CLI, CI/CD, and ephemeral worker architecture

Bring in changes from shannon-npx: npx-distributable CLI package (cli/),
semantic-release CI/CD workflows, ephemeral per-scan worker containers,
TOML config support, setup wizard, and workspace management.

Preserves all shannon-only changes: security hardening (localhost-bound
ports, MCP env allowlist, path traversal guard), updated benchmarks
(XBEN 19/31/35/44), README assets, and prompt injection disclaimer.

Applies security hardening to cli/infra/compose.yml as well.

.github/workflows/release.yml

@@ -0,0 +1,165 @@
+name: Release
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: release-main
+  cancel-in-progress: false
+
+jobs:
+  preflight:
+    name: Preflight
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    outputs:
+      should_release: ${{ steps.probe.outputs.should_release }}
+      version: ${{ steps.probe.outputs.version }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 24
+
+      - name: Install dependencies
+        run: npm clean-install
+
+      - name: Verify dependency signatures
+        run: npm audit signatures
+
+      - name: Probe semantic-release
+        id: probe
+        shell: bash
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+
+          npx semantic-release@25 --dry-run --no-ci 2>&1 | tee semantic-release.log
+
+          if grep -q "The next release version is" semantic-release.log; then
+            echo "should_release=true" >> "$GITHUB_OUTPUT"
+            VERSION=$(grep -oE "The next release version is [0-9]+\.[0-9]+\.[0-9]+" semantic-release.log | grep -oE "[0-9]+\.[0-9]+\.[0-9]+")
+            echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          else
+            echo "should_release=false" >> "$GITHUB_OUTPUT"
+          fi
+
+  publish:
+    name: Publish Docker and npm
+    needs: preflight
+    if: needs.preflight.outputs.should_release == 'true'
+    runs-on: ubuntu-latest
+    environment: release-publish
+    permissions:
+      contents: read
+      id-token: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v4
+        with:
+          username: ${{ vars.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push Docker image
+        id: build
+        uses: docker/build-push-action@v7
+        with:
+          context: .
+          push: true
+          platforms: linux/amd64,linux/arm64
+          provenance: mode=max
+          sbom: true
+          tags: |
+            keygraph/shannon:${{ needs.preflight.outputs.version }}
+            keygraph/shannon:latest
+
+      - name: Install cosign
+        uses: sigstore/cosign-installer@v4.1.0
+
+      - name: Sign Docker image
+        run: cosign sign --yes keygraph/shannon@${{ steps.build.outputs.digest }}
+
+      - name: Verify Docker image signature
+        run: |
+          sleep 10
+          cosign verify \
+            --certificate-oidc-issuer https://token.actions.githubusercontent.com \
+            --certificate-identity https://github.com/${{ github.repository }}/.github/workflows/release.yml@${{ github.ref }} \
+            keygraph/shannon@${{ steps.build.outputs.digest }}
+
+      - name: Configure npm registry
+        uses: actions/setup-node@v6
+        with:
+          node-version: 24
+          registry-url: https://registry.npmjs.org
+
+      - name: Install dependencies
+        run: npm clean-install
+
+      - name: Verify dependency signatures
+        run: npm audit signatures
+
+      - name: Set CLI package version
+        run: npm version "${{ needs.preflight.outputs.version }}" --workspace cli --no-git-tag-version --allow-same-version
+
+      - name: Sync lockfile with bumped versions
+        run: npm i --package-lock-only
+
+      - name: Build CLI
+        run: npm run build:cli
+
+      - name: Publish npm package
+        working-directory: cli
+        run: |
+          if npm view "@keygraph/shannon@${{ needs.preflight.outputs.version }}" version 2>/dev/null; then
+            echo "Version already published, skipping"
+          else
+            npm publish --access public
+          fi
+
+  release:
+    name: Create GitHub release
+    needs: [preflight, publish]
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 24
+
+      - name: Install dependencies
+        run: npm clean-install
+
+      - name: Create GitHub release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: npx semantic-release@25

.github/workflows/rollback.yml

@@ -0,0 +1,124 @@
+name: Rollback
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: "Version to move npm latest and Docker latest to (example: 1.4.2)"
+        required: true
+        type: string
+
+permissions:
+  contents: read
+
+concurrency:
+  group: rollback-latest-${{ github.event.inputs.version }}
+  cancel-in-progress: false
+
+jobs:
+  rollback:
+    name: Roll back npm and Docker latest
+    runs-on: ubuntu-latest
+    environment: release-rollback
+
+    steps:
+      - name: Checkout tags
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Fetch all tags
+        run: git fetch --force --tags
+
+      - name: Validate target version
+        id: target
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          VERSION="${{ inputs.version }}"
+          VERSION="${VERSION#v}"
+
+          case "$VERSION" in
+            ''|*[!0-9.]*)
+              echo "Invalid version: $VERSION"
+              exit 1
+              ;;
+          esac
+
+          if ! [[ "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+            echo "Version must be in semver format X.Y.Z"
+            exit 1
+          fi
+
+          if ! git rev-parse "refs/tags/v$VERSION" >/dev/null 2>&1; then
+            echo "Git tag v$VERSION does not exist"
+            exit 1
+          fi
+
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 24
+          registry-url: https://registry.npmjs.org
+
+      - name: Verify npm package version exists
+        run: npm view "@keygraph/shannon@${{ steps.target.outputs.version }}" version
+
+      - name: Show current npm dist-tags
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_ROLLBACK_TOKEN }}
+        run: npm dist-tag ls @keygraph/shannon
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v4
+        with:
+          username: ${{ vars.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Verify Docker image tag exists
+        run: docker buildx imagetools inspect "keygraph/shannon:${{ steps.target.outputs.version }}"
+
+      - name: Install cosign
+        uses: sigstore/cosign-installer@v4.1.0
+
+      - name: Verify Docker image signature before rollback
+        run: |
+          cosign verify \
+            --certificate-oidc-issuer https://token.actions.githubusercontent.com \
+            --certificate-identity "https://github.com/${{ github.repository }}/.github/workflows/release.yml@refs/heads/main" \
+            "keygraph/shannon:${{ steps.target.outputs.version }}"
+
+      - name: Move Docker latest
+        run: |
+          docker buildx imagetools create \
+            --tag "keygraph/shannon:latest" \
+            "keygraph/shannon:${{ steps.target.outputs.version }}"
+
+      - name: Move npm latest
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_ROLLBACK_TOKEN }}
+        run: npm dist-tag add "@keygraph/shannon@${{ steps.target.outputs.version }}" latest
+
+      - name: Show final npm dist-tags
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_ROLLBACK_TOKEN }}
+        run: npm dist-tag ls @keygraph/shannon
+
+      - name: Verify Docker latest now points to target
+        run: docker buildx imagetools inspect "keygraph/shannon:latest"
+
+      - name: Write summary
+        run: |
+          {
+            echo "## Rollback latest"
+            echo ""
+            echo "- Target version: \`${{ steps.target.outputs.version }}\`"
+            echo "- npm package: \`@keygraph/shannon\`"
+            echo "- Docker image: \`keygraph/shannon\`"
+          } >> "$GITHUB_STEP_SUMMARY"