feat: use nix3-profile if it has to with -i

[dtomvan]

Because nix-env and nix3-profile cannot be used together, I added a check for ~/.local/state/nix/profiles/profile and if it exists, it will install the target package through nix profile install instead of nix-env -iA.

Things done

• nix flake check
• nix build
• cargo clippy
• Checked ./result/bin/comma -i josm works as intended on my system with a ~/.local/state/nix/profiles/profile.
• Checked that before this patch ./result/bin/comma -i josm fails.

[DavHau]

Should we even encourage people to use nix profile? Would it not be better to just remove this installation feature?

[dtomvan]

Should we even encourage people to use nix profile? Would it not be better to just remove this installation feature?

Well, nix profile is a supported feature in nix, and arguably much better than using nix-env for imperative package management. It has a good reason to exist, because it's the only way to allow a user that doesn't have sudo permissions to manage their own environment, without using home-manager. home-manager uses nix profile under the hood anyway:

$ nix profile list --json | jq '.elements["home-manager-path"]'
{
  "active": true,
  "priority": 5,
  "storePaths": [
    "/nix/store/cyij2blljr7bsjw72xnik8pcmk2z3rdw-home-manager-path"
  ]
}

Also, I think we all know why Nix exists and as such will put as much as possible inside of configs, but at the end of the day there are always these edge-cases where you want to install something semi-temporarily. I don't think supporting it with comma is "encouraging" it's use nessecarily...