feat: expand nvim highlights and add audit script

scripts/nvim-audit.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+IFS=$'\n\t'
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+if ! command -v nvim >/dev/null 2>&1; then
+  echo "error: nvim not found on PATH" >&2
+  exit 1
+fi
+
+if [[ ! -f "${root}/dist/nvim/colors/apex-neon.lua" ]]; then
+  echo "error: missing dist/nvim/colors/apex-neon.lua; run 'uv run build.py'" >&2
+  exit 1
+fi
+
+cd "$root"
+nvim --headless -u NONE -U NONE -c "lua dofile('${root}/scripts/nvim_audit.lua')"