Function metric_name_matches 

fn metric_name_matches(table_name: &str, matchers: &[Matcher]) -> bool

Whether a metric name satisfies every __name__ matcher of one selector.

Negated matchers are honoured here, unlike in retrieve_table_names where they keep every table so the caller authorizes the full candidate set: the names reaching this point are already narrowed by the data, so filtering them can only remove names, never widen what a caller gets to see.