ci(bf-414): migrate Pages deploy from GitHub Actions to Argo

- Disable .github/workflows/deploy-pages.yml (renamed to .disabled)
- Deploy now runs via Argo Events sensor → acb-site-pages-build workflow
- Forgejo webhook at webhooks-ci.ardenone.com already registered and active
- Cloudflare API token secret already configured in argo-workflows namespace

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

web/package.json

@@ -2,6 +2,7 @@
   "name": "acb-web",
   "version": "0.1.0",
   "type": "module",
+  "description": "AI Code Battle web frontend - deployed via Argo Workflows to Cloudflare Pages",
   "scripts": {
     "dev": "vite",
     "build": "tsc && vite build",