Build a COSMIC-based Wayland Session for Regolith

Regolith's Wayland session still depends on GNOME for session startup and settings plumbing. That makes the COSMIC path awkward to install and harder to maintain. I want to build regolith-session-cosmic, an experimental Regolith session that starts through cosmic-session, runs Sway, and removes GNOME from the bootstrap path wherever the packaging and runtime audit shows it can go. The project also includes packaging the required COSMIC components through Regolith's Voulage pipeline so the session can be installed without depending on Pop!_OS repositories, finishing the remaining COSMIC-to-Sway keyboard integration in cosmolith, and validating the core session behavior: display, lock and idle, OSD, and settings persistence. The main deliverables are a bootable experimental COSMIC session for Regolith, packaged COSMIC runtime components with reproducible offline builds for the supported target distros, the remaining input integration work in cosmolith, and a documented validation matrix for the supported session path.