「👷」 ci(deadnix): added dead code checker

Author: KeyZox71

.github/workflows/deadnix.yml

@@ -0,0 +1,15 @@
+on: [push]
+
+name: Dead code analysis
+
+jobs:
+  deadnix:
+    name: Deadnix
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v30
+      - uses: cachix/cachix-action@v15
+        with:
+          name: deadnix
+      - uses: astro/deadnix-action@main