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/dependabot.yml

@@ -0,0 +1,43 @@
+version: 2
+updates:
+  # npm dependencies
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 10
+    reviewers:
+      - "blackboxprogramming"
+    labels:
+      - "dependencies"
+      - "automated"
+    commit-message:
+      prefix: "chore"
+      include: "scope"
+
+  # GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 5
+    labels:
+      - "dependencies"
+      - "github-actions"
+    commit-message:
+      prefix: "ci"
+
+  # pip dependencies
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 10
+    labels:
+      - "dependencies"
+      - "python"
+    commit-message:
+      prefix: "chore"