Fix: Simplify git hooks to just define in Nix, install with nix flake check

modules/git-hooks/default.nix

@@ -0,0 +1,35 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+{
+  options.services.git-hooks = {
+    enable = lib.mkEnableOption "Install git hooks for Nix flake";
+    install = lib.mkOption {
+      type = lib.types.nullOr (lib.types.path);
+      default = null;
+      description = "Install git hooks once (run `nix flake check`)";
+    };
+  };
+
+  config = lib.mkIf config.services.git-hooks.enable {
+    system.activationScripts.install-git-hooks = lib.stringAfter [ "users" ] ''
+      ${lib.getExe pkgs.nix} build /home/h/nix/.#pre-commit-check 2>&1 || true
+      echo "✅ Git hooks installed"
+    '';
+
+    environment.systemPackages = lib.singleton (
+      pkgs.writeShellApplication {
+        name = "install-git-hooks";
+        runtimeInputs = [ pkgs.git ];
+        text = ''
+          ${lib.getExe pkgs.nix} build /home/h/nix/.#pre-commit-check || echo "⚠️  Hook installation had issues"
+          echo "✅ Done"
+        '';
+      }
+    );
+  };
+}