Fix critical security vulnerabilities CVE-2025-66478 and CVE-2025-55182

- Update Next.js from 15.4.2 to 16.0.7 (fixes CVE-2025-66478)
- Update React and React-DOM from 19.1.0 to 19.1.2 (fixes CVE-2025-55182)
- Update @next/third-parties from 15.4.4 to 16.0.7
- Update eslint-config-next from 15.4.2 to 16.0.7
- Upgrade GitHub Actions Node.js version from 18 to 20
- Update TypeScript configuration for Next.js 16 compatibility

Both vulnerabilities are CVSS 10.0 critical RCE vulnerabilities in React Server Components.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: crowrish

.github/workflows/deploy.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version: '20'
           cache: 'npm'
 
       - name: Install dependencies