Declarative Without the Elasticity Tax: Margo + Quadlets for Cloned Production Cells

The canonical post-talk write-up of my DevConf.CZ 2026 Brno talk: why Margo + Quadlet is a spec-driven stack for statically configured production cells, how it sits between apt/dnf+Ansible, Docker Compose, and Kubernetes, how the same `.container` descriptor targets WASM tomorrow, and what runs on top in production.