edit.ValidateLanguage had zero callers (only its own godoc referenced it) —
removed.
yaml_json.go: contrary to the audit's claim, the file is NOT entirely dead —
ParseYAML/ParseJSON are live via the Parse() dispatch (parser.go:198-200) and
are kept with their tests. Removed only the genuinely unreachable scaffolding
that nothing constructs or calls: the YAMLNode/JSONNode types, WalkYAML,
GetYAMLNodeText, GetYAMLNodeLocation, QueryYAML, QueryJSON, ValidateYAML,
ValidateJSON, and ToSitterTree, plus their now-orphaned tests. YAML/JSON parsing
behavior is unchanged (TestParseYAML/TestParseJSON/TestRegistryParse_YAML_JSON
still pass).