Function is_safe_unquoted 

pub fn is_safe_unquoted(name: &str, _db: DatabaseKind) -> bool

True when name is safe to emit unquoted in SQL for the given dialect.

“Safe” means: starts with a letter or underscore (lowercase only — PG folds unquoted idents to lowercase, so uppercase letters force a quote), then ASCII letters / digits / underscores, and is not a reserved keyword.