Function auto_meta_files_include

Look up `_meta_files` from matrix values or workflow state and return it as a list of file paths, if present. Matrix takes precedence over state. This enables automatic scoping of ast-grep / js-ast-grep steps to the files produced by a preceding shard step

(
    state: &HashMap<String, serde_json::Value>,
    matrix_values: Option<&HashMap<String, serde_json::Value>>,
)