feat(web): add quiz-button component and schema

[Kneesal]

Background

The quiz button is a visually distinct CTA that opens a modal with an embedded quiz iframe. It was previously implemented as part of a CTA variant, but deserves its own component and CMS schema for clarity and reuse.

Expected outcome

A dedicated quiz-button schema in the CMS and corresponding web component that renders a gradient animated button with a "Quiz" badge, text, and arrow icon. Clicking opens a full-screen modal with an iframe pointing to the configured quiz URL.

Acceptance criteria

• CMS schema sections.quiz-button created with buttonText and iframeSrc attributes
• Schema registered in section and container-slot dynamic zones
• Web component QuizButton renders the gradient animated button matching reference design
• QuizButton modal opens full-screen iframe on click
• GraphQL fragment created for quiz-button
• Section renderer handles ComponentSectionsQuizButton typename
• Seed data includes quiz-button as last block in first section

Possible solution(s)

1. Create quiz-button.json schema, QuizButton.tsx component, fragment, and wire into Section renderer

References

• Existing CTA component pattern in apps/web/src/components/sections/CTA.tsx
• Seed script apps/cms/scripts/seed-easter.cjs

[Kneesal]

Execution Plan

1. CMS schema — Create apps/cms/src/components/sections/quiz-button.json with buttonText (string, required) and iframeSrc (string, required)
2. Register in dynamic zones — Add sections.quiz-button to section.json content components and container-slot.json content components
3. Web fragment — Create apps/web/src/lib/fragments/quiz-button-section.ts
4. Update section fragment — Add ComponentSectionsQuizButton inline fragment to section.ts
5. Update container fragment — Add ComponentSectionsQuizButton inline fragment to container.ts
6. Web component — Create apps/web/src/components/sections/QuizButton.tsx with modal
7. Section renderer — Add ComponentSectionsQuizButton case to Section.tsx
8. Seed data — Add quiz-button block as last item in first section content array
9. Commit & PR