deprecate stylix, fix minor gripes and bugs

util/pre_commit_nix_eval.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root="$(git rev-parse --show-toplevel)"
+flake_ref="path:${repo_root}"
+
+# Use a path flake ref so ignored files, especially the local flake.lock, are
+# visible to Nix even though the repository itself is a Git worktree.
+targets_text="$(
+  nix eval \
+    --raw \
+    --no-write-lock-file \
+    "${flake_ref}#nixosConfigurations" \
+    --apply 'configs: builtins.concatStringsSep "\n" (builtins.attrNames configs)'
+)"
+
+targets=()
+while IFS= read -r target; do
+  if [ -n "${target}" ]; then
+    targets+=("${target}")
+  fi
+done <<< "${targets_text}"
+
+if [ "${#targets[@]}" -eq 0 ]; then
+  echo "No nixosConfigurations found to evaluate." >&2
+  exit 1
+fi
+
+for target in "${targets[@]}"; do
+  echo "Evaluating nixosConfigurations.${target}.config.system.build.toplevel"
+  nix eval \
+    --raw \
+    --no-write-lock-file \
+    "${flake_ref}#nixosConfigurations.${target}.config.system.build.toplevel.drvPath" \
+    >/dev/null
+done