ci: check formatting

Signed-off-by: Patrizio Bekerle <patrizio@bekerle.com>

Author: pbek

.github/workflows/format-check.yml

@@ -0,0 +1,26 @@
+name: 📄 Check formatting
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  format-check:
+    name: 📄 Check code formatting
+    runs-on: ubuntu-latest
+    steps:
+      - name: 🧰 Checkout code
+        uses: actions/checkout@v6
+      - name: ⚙️ Install Nix
+        uses: cachix/install-nix-action@v31
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - name: 🔒 Cache dependencies
+        uses: cachix/cachix-action@v16
+        with:
+          name: devenv
+      - name: 🔧 Install devenv.sh
+        run: nix profile add nixpkgs#devenv
+      - name: 🔨 Build the devenv shell and run formatting check
+        run: devenv shell "just format"