Abhay-kavachi/Relay ? reverse-engineered prompt

Build me a web app that lets me visually design and run a lead workflow, then watch each step execute one by one so I can see exactly what happened. I want a top area where I can pick a few preset demo scenarios, like a high value lead, a medium lead, a low quality lead, and a failure recovery case, then click Run Workflow and see the nodes light up as data moves through the flow.

Please include a human approval pause when the workflow needs it, with a clear modal to approve or reject, and then continue the run after approval. I also want to click any step and inspect the full trace, including what went in, what came out, how long it took, and whether it succeeded, failed, waited, or was skipped. Add a history panel for previous runs too.

Make it feel polished and deterministic, with fake demo actions only, no real external side effects. Use current docs online if you need to.