Add github actions workflow for CI tests

.github/workflows/test.yml

@@ -0,0 +1,17 @@
+name: "Test"
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+  schedule:
+    - cron: '42 7 * * *'
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v30
+      - name: Execute unit tests
+        run: nix flake check