Use gimp-console when available, GIMP 3 Script-Fu API, and temp .scm
batch files so layer stacking works without a display.
Co-authored-by: Cursor <cursoragent@cursor.com>
Collect prior pipeline step outputs per image and stack them into XCF files via headless GIMP Script-Fu.
Co-authored-by: Cursor <cursoragent@cursor.com>