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>

roles/docker/templates/kanboard-compose.yml.j2

@@ -0,0 +1,32 @@
+services:
+  kanboard:
+    image: kanboard/kanboard:latest
+    container_name: kanboard
+    restart: unless-stopped
+    environment:
+      - PLUGIN_INSTALLER=true
+      - DB_DRIVER=sqlite
+    volumes:
+      - kanboard_data:/var/www/app/data
+      - kanboard_plugins:/var/www/app/plugins
+    extra_hosts:
+      - "host.docker.internal:host-gateway"
+      - "{{ subdomains.auth }}:{{ docker.hairpin_ip }}"
+    labels:
+      glance.name: Kanboard
+      glance.icon: si:kanboard
+      glance.url: https://{{ subdomains.kanboard }}/
+      glance.description: Project management and Kanban boards
+      glance.id: kanboard
+      mag37.dockcheck.update: true
+
+volumes:
+  kanboard_data:
+    driver: local
+  kanboard_plugins:
+    driver: local
+
+networks:
+  default:
+    external: true
+    name: {{ docker.network_name }}