feat(workflow-form): embed the read-only workflow preview #8020

Task Summary

Show the workflow graph read-only inside the form so a reader sees the steps that will run.

• reuse workflow-editor + mini-map (same as the workspace/Hub)
• WorkflowEditorComponent: add a structureLocked input + a container ResizeObserver so the paper draws correctly when mounted outside the canvas
• embed with structureLocked on and center on open
• reuse the mini-map at its natural size (host .box only positions it, like the workspace/Hub) so the graph isn't clipped behind the mini-map toolbar

Task Type

• Refactor / Cleanup
• DevOps / Deployment / CI
• Testing / QA
• Documentation
• Performance
• Other