ci(nix): re-enable

.github/workflows/nix.yml

@@ -0,0 +1,36 @@
+name: Nix Test & Cache
+
+on:
+  push:
+    branches: [main]
+    paths: ["**.nix", "**.ts", "**.nix"]
+  pull_request:
+    paths: ["**.nix", "**.ts", "**.nix"]
+  workflow_dispatch:
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: ["ubuntu-latest", "macos-latest"]
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+
+      - name: Setup cachix
+        uses: cachix/cachix-action@v12
+        with:
+          name: "catppuccin"
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+          skipPush: ${{ github.ref != 'refs/heads/main' }}
+
+      - name: Flake check
+        run: nix flake check -Lv
+
+      - name: Build packages
+        run: nix build -L .