feat: add .envrc

.envrc

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+if type nix-shell >/dev/null 2>&1; then
+    use flake
+else
+    echo "nix-shell is not available, please install Nix or run the environment manually."
+fi
+
+# vim: syntax=bash