[Feature Request/Offer] Selecting a PNG created by FramePack as a still for the anim populates all UI

I see this handled a couple ways in pending commits. I'm implementing as JSON wrapped in the image metadata, currently Extra.FramePackSettings, but I also see individual metadata fields for just prompt and seed, and it looks like the ability to save/load settings directly. Having the drag-and-drop helps me since I'm so used to ComfyUI and using every image as a "stealth fork", but would this be more helpful or annoying to others? A dialogue choice popped up when dropping in an image would be all the same to me but simple to add if that would be less...surprising for others.

SVC

Review the pending commits and the existing approaches to image metadata, including Extra.FramePackSettings, separate prompt and seed fields, and direct settings save/load. Clarify whether dropping or selecting a FramePack PNG should populate the UI automatically or prompt first, then define completion around one agreed behavior and its interaction with still-image animation setup.

Written by the indexing model from the issue text.