Current node showed "negative prompt" only on values from a workflow. A material's blocks carried no role, and when a picture and a workflow held the same text the merged card kept the picture's empty one, so a negative prompt could be offered to a positive box with nothing to say so.
- api/materials.py works the role out by what the prompt was wired to, as the material details already do; it reads the stored workflow, so pictures kept earlier get it too.
- node_parameter_sets.js takes the role from whichever source knows it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
