ci: add GitHub Actions workflows

- Security scanning (CodeQL, dependency scan, secret scan)
- Auto-deployment to Cloudflare/Railway
- Self-healing with auto-rollback
- Dependabot for dependency updates

Deployed by: Phase 6 GitHub CI/CD automation

.github/workflows/security-scan.yml

@@ -0,0 +1,55 @@
+name: 🔒 Security Scan
+
+on:
+  push:
+    branches: [main, master, dev]
+  pull_request:
+    branches: [main, master]
+  schedule:
+    - cron: '0 0 * * 0'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  security-events: write
+  actions: read
+
+jobs:
+  codeql:
+    name: CodeQL Analysis
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        language: ['javascript', 'typescript', 'python']
+    
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+      
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v3
+      
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+
+  dependency-scan:
+    name: Dependency Scan
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      
+      - name: Run npm audit
+        if: hashFiles('package.json') != ''
+        run: npm audit --audit-level=moderate || true
+      
+      - name: Dependency Review
+        uses: actions/dependency-review-action@v4
+        if: github.event_name == 'pull_request'