Add 03-opensource/privacy-security/vaultwarden.md covering deployment with Docker Compose, Caddy reverse proxy, client setup, access model via Tailscale, and SQLite backup. Remove KeePassXC from backlog. Article count: 31 → 32. Open source section: 4 → 5. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>