Switches the nix branch prefix from release to nixos. release-YY.MM are
the development branches, while nixos-YY.MM are the intended ones for
use.
Targeting release risks pinning untested code and often leads to
rebuilding big packages when the nix cache has not caught up.
Flake lock file updates:
• Updated input 'nixpkgs':
'github:NixOS/nixpkgs/8cb14136bb517eba32a565a682861eef55c45a06'
(2026-06-29)
→ 'github:NixOS/nixpkgs/4382ed2b7a6839d4280a9b386db49cbc5907414d'
(2026-07-16)
