use Nixpkgs from npins in the flake

flake.nix

@@ -1,6 +1,5 @@
 {
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-24.11"; # consumed by flake-parts
     flake-parts.url = "github:hercules-ci/flake-parts";
     git-hooks.url = "github:cachix/git-hooks.nix";
     nixops4.follows = "nixops4-nixos/nixops4";
@@ -11,9 +10,11 @@
     inputs@{ flake-parts, ... }:
     let
       sources = import ./npins;
+      inherit (import "${sources.flake-inputs}/lib.nix") import-flake;
       inherit (sources) git-hooks agenix;
+      nixpkgs = import-flake sources.nixpkgs;
     in
-    flake-parts.lib.mkFlake { inherit inputs; } {
+    flake-parts.lib.mkFlake { inputs = inputs // { inherit nixpkgs; }; } {
       systems = [
         "x86_64-linux"
         "aarch64-linux"

npins/sources.json

@@ -25,6 +25,22 @@
       "url": null,
       "hash": "1w2gsy6qwxa5abkv8clb435237iifndcxq0s79wihqw11a5yb938"
     },
+    "flake-inputs": {
+      "type": "GitRelease",
+      "repository": {
+        "type": "GitHub",
+        "owner": "fricklerhandwerk",
+        "repo": "flake-inputs"
+      },
+      "pre_releases": false,
+      "version_upper_bound": null,
+      "release_prefix": null,
+      "submodules": false,
+      "version": "1.1",
+      "revision": "6461d0b56e790bf289af07c5e5261abbf4f536af",
+      "url": "https://api.github.com/repos/fricklerhandwerk/flake-inputs/tarball/1.1",
+      "hash": "03mwisvr1mc3nd33nvg4bvcyxjxpm4lwhwym39r0768cm1007ixl"
+    },
     "flake-parts": {
       "type": "Git",
       "repository": {