ci: add deploy-to-Hostinger workflow

Rsync over SSH on push to main. Runs CI first, then syncs
production files to wp-content/plugins/peptide-reconstitution-calculator/
on Hostinger. Includes LiteSpeed cache purge and health check.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/deploy.yml

@@ -0,0 +1,73 @@
+name: Deploy to Hostinger
+
+on:
+  push:
+    branches: [ main ]
+
+permissions:
+  contents: read
+
+# Cancel previous deploys if a new push arrives while one is running.
+concurrency:
+  group: deploy-peptide-reconstitution-calculator
+  cancel-in-progress: true
+
+jobs:
+  # ── Run CI first ─────────────────────────────────────────────────
+  ci:
+    name: Pre-deploy CI
+    uses: ./.github/workflows/ci.yml
+
+  # ── Deploy via rsync over SSH ────────────────────────────────────
+  deploy:
+    needs: ci
+    name: Deploy to Production
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup SSH key
+        run: |
+          mkdir -p ~/.ssh
+          echo "${{ secrets.SSH_PRIVATE_KEY }}" > ~/.ssh/deploy_key
+          chmod 600 ~/.ssh/deploy_key
+          ssh-keyscan -p ${{ secrets.SSH_PORT }} ${{ secrets.SSH_HOST }} >> ~/.ssh/known_hosts 2>/dev/null
+
+      - name: Deploy via rsync
+        run: |
+          rsync -avz --delete \
+            --exclude '.git' \
+            --exclude '.github' \
+            --exclude 'tests' \
+            --exclude 'phpunit.xml.dist' \
+            --exclude 'composer.json' \
+            --exclude 'composer.lock' \
+            --exclude 'vendor' \
+            --exclude 'phpcs.xml.dist' \
+            --exclude 'ARCHITECTURE.md' \
+            --exclude 'CONVENTIONS.md' \
+            --exclude 'CHANGELOG.md' \
+            -e "ssh -i ~/.ssh/deploy_key -p ${{ secrets.SSH_PORT }}" \
+            ./ ${{ secrets.SSH_USERNAME }}@${{ secrets.SSH_HOST }}:~/domains/peptiderepo.com/public_html/wp-content/plugins/peptide-reconstitution-calculator/
+
+      - name: Purge LiteSpeed Cache
+        run: |
+          ssh -i ~/.ssh/deploy_key -p ${{ secrets.SSH_PORT }} \
+            ${{ secrets.SSH_USERNAME }}@${{ secrets.SSH_HOST }} \
+            "cd ~/domains/peptiderepo.com/public_html && find wp-content/litespeed/ -type f -delete 2>/dev/null; touch .lscache_purge 2>/dev/null || true"
+
+      - name: Health check
+        run: |
+          sleep 5
+          STATUS=$(curl -s -o /dev/null -w "%{http_code}" https://peptiderepo.com)
+          if [ "$STATUS" != "200" ] && [ "$STATUS" != "403" ]; then
+            echo "ERROR: Site returned unexpected HTTP $STATUS after deploy"
+            exit 1
+          fi
+          echo "Site is responsive (HTTP $STATUS)"
+
+      - name: Cleanup
+        if: always()
+        run: rm -f ~/.ssh/deploy_key