pub fn diagnose(meta: &Value) -> Vec<ConfigIssue>Expand description
Diagnose a config surface (a root’s prov: block or a config document’s
top-level mapping): one ConfigIssue per key apply would silently ignore.
Recognized keys are checked for a value prov can parse; unrecognized keys
are reported only when they closely resemble a real axis at their level (a
likely typo). Returns empty for a clean config.