Add flake.nix to support NixOS
This PR adds a flake.nix that exposes the theme as a package output(#8 (closed)). I severely underestimated how tricky this would be
What this does
- Allows NixOS users to set the theme directly via:
services.displayManager.sddm.theme = "silent"; - Updates shell script shebangs to
#!/usr/bin/env bashfor better portability (some systems like NixOS don't havebashin/bin)
Due to how qt6 themes are on nixos it might not be obvious on how to use the flake, maybe should add instructions in README?.
Let me know if you'd like anything changed or if I should squash the commits. (This is my first open source contribution ever, so feedback is very welcome!)