add dev flake pattern

This allows us to have dev dependencies which are not propagated to the user.

flake.lock

@@ -67,52 +67,6 @@
         "type": "github"
       }
     },
-    "flake-utils": {
-      "inputs": {
-        "systems": [
-          "systems"
-        ]
-      },
-      "locked": {
-        "lastModified": 1731533236,
-        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "ixx": {
-      "inputs": {
-        "flake-utils": [
-          "nuschtos",
-          "flake-utils"
-        ],
-        "nixpkgs": [
-          "nuschtos",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1748294338,
-        "narHash": "sha256-FVO01jdmUNArzBS7NmaktLdGA5qA3lUMJ4B7a05Iynw=",
-        "owner": "NuschtOS",
-        "repo": "ixx",
-        "rev": "cc5f390f7caf265461d4aab37e98d2292ebbdb85",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NuschtOS",
-        "ref": "v0.0.8",
-        "repo": "ixx",
-        "type": "github"
-      }
-    },
     "nix-darwin": {
       "inputs": {
         "nixpkgs": [
@@ -174,41 +128,15 @@
         "url": "https://nixos.org/channels/nixpkgs-unstable/nixexprs.tar.xz"
       }
     },
-    "nuschtos": {
-      "inputs": {
-        "flake-utils": [
-          "flake-utils"
-        ],
-        "ixx": "ixx",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1749730855,
-        "narHash": "sha256-L3x2nSlFkXkM6tQPLJP3oCBMIsRifhIDPMQQdHO5xWo=",
-        "owner": "NuschtOS",
-        "repo": "search",
-        "rev": "8dfe5879dd009ff4742b668d9c699bc4b9761742",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NuschtOS",
-        "repo": "search",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "data-mesher": "data-mesher",
         "disko": "disko",
         "flake-parts": "flake-parts",
-        "flake-utils": "flake-utils",
         "nix-darwin": "nix-darwin",
         "nix-select": "nix-select",
         "nixos-facter-modules": "nixos-facter-modules",
         "nixpkgs": "nixpkgs",
-        "nuschtos": "nuschtos",
         "sops-nix": "sops-nix",
         "systems": "systems",
         "treefmt-nix": "treefmt-nix"