/** Parses booleans and case-insensitive `true`/`false` string tokens. */
export function parseBoolean(value: unknown): boolean | undefined {
  if (typeof value === "boolean") {
    return value;
  }
  if (typeof value !== "string") {
    return undefined;
  }
  const normalized = value.trim().toLowerCase();
  if (normalized === "true") {
    return true;
  }
  if (normalized === "false") {
    return false;
  }
  return undefined;
}