frontend-prototype-explorerlisted

# Frontend Prototype Explorer Maturity: experimental. Validate a consequential UI or state decision through a disposable experiment before production implementation. ## Purpose Answer one unresolved question with the cheapest runnable artifact. Preserve the decision and evidence, not an accidental production implementation. ## When To Use - Compare interactive UI alternatives when descriptions cannot settle usability. - Exercise a state model through cancellation, delayed responses, or recovery. - Investigate a consequential choice that source and documentation cannot settle. ## When Not To Use - Implementing an already approved layout or feature. - A small style edit, routine bugfix, or question answered by existing source. - Planning-only requests that do not authorize building an experiment. - Backend, production data, benchmarking, or new infrastructure outside scope. ## Required Context 1. Apply the active runtime entrypoint (`AGENTS.md` for project targets or the native runtime prelude for plugin targets) and the confirmed question and constraints. 2. Inspect only the existing stack, commands, and affected ownership needed. 3. Read `common/domain-glossary-rules.md` when domain terms matter. 4. Read `common/verification-loop-rules.md` for executable observations and `common/rendered-visual-verification-policy.md` if UI interaction is needed. ## Tool Contract Use available project-file and command capabilities. A callable browser is required for claims