docs: redesign README and launch GitHub Pages website

.github/workflows/pages.yml

@@ -0,0 +1,65 @@
+name: Deploy MARGINAL website
+
+on:
+  push:
+    branches: ["main"]
+    paths:
+      - "site/**"
+      - "assets/marginal-readme-hero.png"
+      - "demos/killer-demo/**"
+      - ".github/workflows/pages.yml"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Configure Pages
+        uses: actions/configure-pages@v5
+      - name: Assemble website
+        shell: bash
+        run: |
+          set -euo pipefail
+          rm -rf _site
+          mkdir -p _site/assets _site/demo
+          cp -R site/. _site/
+          cp assets/marginal-readme-hero.png _site/assets/marginal-readme-hero.png
+          cp -R demos/killer-demo/. _site/demo/
+          touch _site/.nojekyll
+      - name: Verify generated website
+        shell: bash
+        run: |
+          set -euo pipefail
+          test -f _site/index.html
+          test -f _site/styles.css
+          test -f _site/app.js
+          test -f _site/robots.txt
+          test -f _site/sitemap.xml
+          test -f _site/assets/marginal-readme-hero.png
+          test -f _site/demo/RESULTS.md
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

CHANGELOG.md

@@ -19,7 +19,6 @@ All notable changes to MARGINAL are documented here. The project follows Semanti
 - provider-neutral `Outcome` contract separated from action-level realized gain;
 - schema-versioned `JsonlDecisionLedger` with strict envelope validation, run/task/trajectory/engine/model correlation, task/outcome consistency checks, and monotonic sequencing;
 - `PrivacyProfile` with `local_full`, keyed `safe_telemetry`, and separate `aggregate_export` modes;
-- privacy-preserving aggregate export with a configurable minimum group size of five by default;
 - field classification for safe-by-default, pseudonymous, and potentially sensitive evidence;
 - HMAC-SHA-256 identifier pseudonymization, UTC-day timestamp generalization, strict free-text removal, and local 256-bit key management;
 - opaque random local identifier generation for runs, tasks, and other caller-defined namespaces;
@@ -35,6 +34,11 @@ All notable changes to MARGINAL are documented here. The project follows Semanti
 
 ### Changed
 
+- redesigned the repository README as a concise, SEO-oriented technical landing page;
+- added a dependency-free, responsive, accessible GitHub Pages product website;
+- consolidated the product website, hero asset, and Killer Demo into one Pages deployment;
+- documented website ownership, deployment, accessibility, privacy, and evidence guardrails.
+
 - `Decision` is backward compatible but now carries recommendation, mode, reason-code, uncertainty, confidence, and estimator metadata;
 - `MarginalPolicy` now has a stable identity and supports both versioned and legacy custom estimators;
 - `Treasury.summary()` includes mode, policy, estimator, observed overruns, failed settlements, outcomes, and estimator observations;

PACKAGE_MANIFEST.json

@@ -0,0 +1,22 @@
+{
+  "package_type": "repository overlay",
+  "repository": "SignalLayerLabs/Marginal",
+  "generated_on": "2026-08-06",
+  "files": [
+    ".github/workflows/pages.yml",
+    "CHANGELOG.md",
+    "README.md",
+    "VISUAL_STUDIO_COMMIT_PROMPT.md",
+    "docs/superpowers/plans/2026-08-06-readme-pages.md",
+    "docs/superpowers/specs/2026-08-06-readme-pages-design.md",
+    "docs/website.md",
+    "scripts/validate_readme_pages.py",
+    "site/404.html",
+    "site/app.js",
+    "site/index.html",
+    "site/robots.txt",
+    "site/sitemap.xml",
+    "site/styles.css"
+  ],
+  "important": "Ensure exactly one workflow invokes actions/deploy-pages."
+}