feat: unify web and feed result surfaces

[gildesmarais]

Summary

• align the web result state and rendered feed surface around a shared visual language
• move shared presentation rules into public/shared-ui.css and simplify feed/result action copy
• update frontend and smoke coverage for the revised menu and success-state layout

Verification

• docker compose -f .devcontainer/docker-compose.yml run --rm app make setup
• docker compose -f .devcontainer/docker-compose.yml run --rm app make ready
• browser smoke in chrome-devtools at http://127.0.0.1:4001/ covering utility menu, token gate, and success/result state