- Use 'jq -Rs split' instead of 'jq -R' to properly handle base64 data URIs that may contain embedded newlines in the data - Fix double-nesting of subject_reference array causing API error 2013 - Also fix: base64 -w 0 to avoid line wrapping in base64 output - Write payload to temp file for curl to avoid shell arg length limits - Add full response output on API error for easier debugging Fixes #53