.read_ars_metadata: Read ARS metadata from disk
Description
Internal helper that validates the ARS file extension and dispatches to the
JSON or XLSX reader before returning the harmonised metadata list.
Usage
.read_ars_metadata(ARS_path)
Value
A list containing harmonised metadata tables, or `NULL` if the file
cannot be parsed.
Arguments
- ARS_path
Path to the ARS metadata file (JSON or XLSX).