Is your feature request related to a problem?

When a pipeline produces an unexpected result, there is no way to inspect what each operator did to the image. The only output is the final processed image, so diagnosing which step caused a problem requires removing blocks one at a time and re-running manually.

Describe the solution you'd like

A debug toggle in the toolbar that, when enabled, causes the backend to capture the image state after every operator and return it alongside the final result. The preview pane should display these intermediate frames with prev/next navigation and a step indicator showing which operator produced each frame, so users can step through the pipeline and see exactly what each operation did.

Describe alternatives you've considered

Implementing this entirely on the frontend by running the pipeline one step at a time with separate API calls. Rejected because it would multiply network round-trips proportionally to pipeline length and produce inconsistent timing data.

Additional context
Any other context or screenshots.

I will be working on this issue.