Add CI/CD pipeline with automated testing and SFTP deployment

Introduces GitHub Actions workflows for continuous integration and
deployment. CI runs PHP linting (7.4, 8.1, 8.3), PHPCS with WordPress
coding standards, PHPUnit tests across PHP versions, and JS syntax
checks. Deployment to Hostinger via FTPS triggers on push to main
after all CI checks pass, with optional LiteSpeed cache purge.

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

.github/workflows/deploy.yml

@@ -0,0 +1,76 @@
+name: Deploy to WordPress
+
+on:
+  push:
+    branches: [ main ]
+
+permissions:
+  contents: read
+
+# Cancel previous deploys if a new push arrives while one is running.
+concurrency:
+  group: deploy-production
+  cancel-in-progress: true
+
+jobs:
+  # ── Run tests first ──────────────────────────────────────────────
+  test:
+    name: Pre-deploy tests
+    uses: ./.github/workflows/ci.yml
+
+  # ── Deploy via SFTP ──────────────────────────────────────────────
+  deploy:
+    name: Deploy to Hostinger
+    runs-on: ubuntu-latest
+    needs: test  # Only deploy if all CI checks pass
+    environment: production
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Deploy plugin files via SFTP
+        uses: SamKirkland/FTP-Deploy-Action@v4.3.5
+        with:
+          server:   ${{ secrets.SFTP_HOST }}
+          username: ${{ secrets.SFTP_USER }}
+          password: ${{ secrets.SFTP_PASS }}
+          port:     ${{ secrets.SFTP_PORT || 22 }}
+          protocol: ftps
+          local-dir:  ./
+          server-dir: ${{ secrets.WP_PLUGIN_PATH }}
+          exclude: |
+            **/.git*
+            **/.git*/**
+            .github/**
+            tests/**
+            vendor/**
+            node_modules/**
+            composer.json
+            composer.lock
+            phpunit.xml.dist
+            .phpcs.xml.dist
+            peptide-news-plugin/**
+            README.md
+            .editorconfig
+
+      - name: Purge LiteSpeed Cache
+        if: success()
+        run: |
+          # Trigger a cache purge via the WordPress REST API.
+          # This requires an Application Password set up in WordPress.
+          if [ -n "${{ secrets.WP_APP_PASSWORD }}" ]; then
+            curl -s -X POST \
+              -u "${{ secrets.WP_ADMIN_USER }}:${{ secrets.WP_APP_PASSWORD }}" \
+              "${{ secrets.WP_SITE_URL }}/wp-json/peptide-news/v1/cache-purge" \
+              --max-time 15 || echo "Cache purge skipped (endpoint not available)"
+          else
+            echo "No WP_APP_PASSWORD set — skipping remote cache purge."
+            echo "Remember to purge LiteSpeed Cache manually after deploy."
+          fi
+
+      - name: Deploy summary
+        run: |
+          echo "## Deployment Complete" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "- **Branch:** \`${{ github.ref_name }}\`" >> $GITHUB_STEP_SUMMARY
+          echo "- **Commit:** \`${{ github.sha }}\`" >> $GITHUB_STEP_SUMMARY
+          echo "- **Deployed to:** ${{ secrets.WP_SITE_URL || 'peptiderepo.com' }}" >> $GITHUB_STEP_SUMMARY