feat(flake): add formatter

.github/workflows/eval-format.yml

@@ -0,0 +1,18 @@
+name: "Eval"
+
+on:
+  push:
+    branches: 'master'
+  pull_request_target:
+
+jobs:
+  format:
+    name: Format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: "actions/checkout@v4"
+      - uses: "cachix/install-nix-action@V28"
+        with:
+          nix_path: nixpkgs=channel:nixpkgs-unstable
+      - name: Check formatting
+        run: nix fmt -- -c .

flake.nix

@@ -24,6 +24,8 @@
             ...
           }:
           rec {
+            formatter = pkgs.nixfmt-rfc-style;
+
             packages = rec {
               wrangler = pkgs.callPackage ./pkgs/wrangler/package.nix { };
               default = wrangler;