feat: add Kanboard project management service

- Add kanboard subdomain to domains.yml
- Create Docker Compose template with SQLite backend and plugin store enabled
- Add Ansible task for service deployment
- Configure Caddy reverse proxy routing
- Integrate with productivity services category

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

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

dns.yml

@@ -53,6 +53,8 @@
             ip: "152.53.36.98"
           - name: pdg
             ip: "152.53.36.98"
+          - name: kanboard
+            ip: "152.53.36.98"
       - name: nerder.land
         dns_records:
           - name: "forms"