TOML and Nix config export (litmus-ct1q)
Copy TOML button (canonical format) and Nix snippet (programs.kitty.settings attrset). Clipboard API.
Summary of Changes
Added export::to_toml() and export::to_nix() in litmus-model. TOML exports in litmus canonical format, Nix exports as an attrset suitable for programs.kitty.settings. Both available via ExportButtons UI.