fix(paws): use hash instead of narHash

[isabelroses]

between nix 2.26 and 2.28 theres a difference in the output json from nix flake prefetch

nix 2.26:

{
  "hash": "sha256-JYHsWUKKBzYEc5iSiyYsYm5Kz73PPN0php0JfR9wMxg=",
  "locked": {
    "__final": true,
    "lastModified": 1744992325,
    "narHash": "sha256-JYHsWUKKBzYEc5iSiyYsYm5Kz73PPN0php0JfR9wMxg=",
    "owner": "catppuccin",
    "repo": "atuin",
    "rev": "bd403cf7f0324aafc3f2462aeb9c2be6e230c9ac",
    "type": "github"
  },
  "original": {
    "owner": "catppuccin",
    "repo": "atuin",
    "type": "github"
  },
  "storePath": "/nix/store/0b398ha6q0gbzjswbdxhh8r1fgiyjrgf-source"
}

nix 2.18:

{
  "hash": "sha256-JYHsWUKKBzYEc5iSiyYsYm5Kz73PPN0php0JfR9wMxg=",
  "locked": {
    "__final": true,
    "lastModified": 1744992325,
    "owner": "catppuccin",
    "repo": "atuin",
    "rev": "bd403cf7f0324aafc3f2462aeb9c2be6e230c9ac",
    "type": "github"
  },
  "original": {
    "owner": "catppuccin",
    "repo": "atuin",
    "type": "github"
  },
  "storePath": "/nix/store/0b398ha6q0gbzjswbdxhh8r1fgiyjrgf-source"
}

[getchoo]

Reported upstream in NixOS/nix#13049. Thanks!