devshell: support direnv

Author: jaen

.envrc

@@ -0,0 +1,13 @@
+if has nix; then
+  # Are flake supported and enabled?
+  if nix show-config | grep experimental-features | grep -q flakes; then
+    # Do we have nix-direnv?
+    if ! has nix_direnv_version || ! nix_direnv_version 3.0.4; then
+      source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.4/direnvrc" "sha256-gMHkKyEOq/T0XmHKgz+pN+fUQC/1EKPAuOtYM95lLnU="
+    fi
+
+    use flake
+  else
+    use nix
+  fi
+fi

.gitignore

@@ -5,3 +5,5 @@ __pycache__
 .pytest_cache
 .mypy_cache
 .ruff_cache
+
+.direnv