feat: add real Stripe integration, e2e tests, and Pi deployment

Replace documentation-only repo with working code:

- Stripe integration: webhook handler (8 event types), billing API
  (customers, checkout, payments, subscriptions, invoices)
- Express API server with health endpoint, structured logging
- E2E tests (Playwright): health, webhook signature verification,
  billing API validation
- Unit tests: webhook event handler coverage for all event types
- Pi deployment: deploy.sh (rsync + systemd), NGINX load balancer
  across Pi cluster, Docker support
- CI/CD: test workflow, Pi deploy workflow, updated auto-deploy
  and self-healing to run real tests before deploying
- Move resume docs to docs/ to separate code from documentation

https://claude.ai/code/session_01Mf5Pg82fV6BTRS9GnpV7nr

.github/workflows/test.yml

@@ -0,0 +1,51 @@
+name: Test
+
+on:
+  push:
+    branches: [main, master, 'claude/**']
+  pull_request:
+    branches: [main, master]
+
+env:
+  NODE_VERSION: '20'
+
+jobs:
+  unit-tests:
+    name: Unit Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+          cache: 'npm'
+
+      - run: npm ci
+
+      - name: Run unit tests
+        run: npm test
+
+  e2e-tests:
+    name: E2E Tests
+    runs-on: ubuntu-latest
+    needs: unit-tests
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+          cache: 'npm'
+
+      - run: npm ci
+
+      - name: Install Playwright
+        run: npx playwright install --with-deps chromium
+
+      - name: Run E2E tests
+        run: npm run test:e2e
+        env:
+          STRIPE_SECRET_KEY: sk_test_placeholder
+          STRIPE_WEBHOOK_SECRET: whsec_test_secret
+          NODE_ENV: test