Add nixos test CI

Author: LennyPenny

.github/workflows/checks.yml

@@ -0,0 +1,19 @@
+name: Run Nix Checks
+
+on:
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  checks:
+    name: Run all checks
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      
+      - name: Install Lix
+        uses: samueldr/lix-gha-installer-action@v2026-02-22
+      
+      - name: Run all checks
+        run: lix build .#checks.x86_64-linux --print-build-logs