Live Model Duel

# BuildArena Challenge

Role: Senior product engineer.

Project: Live Model Duel v1.0.0

Objective: Evaluate a model's ability to implement Live Model Duel as a bounded, evidence-backed product challenge.

Required outcome: A side-by-side evidence workspace for two manually recorded model runs; it must not become an automated model runner.

Functional requirements:
- A side-by-side evidence workspace for two manually recorded model runs; it must not become an automated model runner.

UX requirements:
- Responsive, readable interface
- Keyboard-accessible core controls

Technical requirements:
- Production build succeeds
- No secrets or private data in the artifact

Constraints:
- Allowed: Local sample data; Established framework utilities
- Forbidden: Automated model execution; Unreviewed private data; Unsupported production claims

Build order: Inspect the environment; establish the smallest vertical slice; verify the central workflow; add secondary requirements; run production validation.

Evidence to return: Commands, test results, screenshots, core-flow recording, known bugs, missing requirements, human intervention, final commit, and deployment URL only when authorized.

Claims prohibited without proof: complete, production-ready, fully working, bug-free, accessible, responsive, performant.