Validate a marks file against the markermd JSON Schema
validate_marks_file.RdStructurally validates a marks YAML (or JSON) file against the bundled
JSON Schema (inst/schema/markermd-marks.json). This is an optional check
aimed at tooling and LLM-generated files; the authoritative validation
(including matching item descriptions against the project's rubric) happens
in read_marks_yaml() and marks_import(). Requires the suggested
jsonvalidate package.
Value
TRUE when the file conforms to the schema, otherwise FALSE with
the validation errors attached as attributes (see jsonvalidate::json_validate()).