Read a JSON file, apply processor to every matching scalar value, and write the result.
filter_keys is a list of dot-notation key paths to restrict processing to; empty means all values.
Key insertion order is preserved via serde_json’s preserve_order feature.
Read a JSON file, apply processor to every matching scalar value, and return the result in memory.
filter_keys is a list of dot-notation key paths to restrict processing to; empty means all values.