Introduce Neko container template with installer and metadata. Adds ct/neko.sh (container install entrypoint and update routine), install/neko-install.sh (detailed install/build steps: fetch GitHub release m1k1o/neko, build client/server, configure supervisord, systemd service, runtime users, plugins, and default neko.yaml), and json/neko.json (app metadata, resources, port 8080, default credentials and notes). Enables automated provisioning of the Neko WebRTC virtual browser on Debian 12 with default CPU/RAM/disk values.
