save method
Write the store under root/.dialect/state.json, creating the
directory if needed. Canonical form: version first, then remaining
top-level keys sorted, checks keys sorted, 2-space indent, trailing
newline.
Implementation
void save(String root) {
final file = File(p.join(root, '.dialect', 'state.json'));
file.parent.createSync(recursive: true);
file.writeAsStringSync(encode());
}