By: Ammar Nanjiani <ammar.nanjiani@gmail.com>
feat(aragorn): install uv system-wide Add pkgs.uv to environment.systemPackages so every user, including Hermes, can run uv/uvx from /run/current-system/sw/bin. This is for ad-hoc Python tools such as youtube-transcript-api, not a Hermes-only extra.