feat: tests and fixes for personalised frontend pages (Quiz, Assignment, Certificate)

[Copilot]

The personalised user-facing pages existed as React entry points but had no tests, a missing locale key causing a blank heading, and a stale filename reference in the Vite config.

Fixes

• vite.config.js: Corrected optimizeDeps.entries entry QuizPublic.jsx → Quiz.jsx (file never existed under that name)
• CertificateFormView: Added missing form_title locale key — the certificate form was rendering an empty <h4> because the key was never passed from the Django view

Testability

Each personalised component was an entry point with no export, making unit testing impossible. Added named exports alongside the existing render() call:

// before
render({ children: <Quiz /> });

// after
export { Quiz };
render({ children: <Quiz /> });

New tests (40 total across 4 files)

File	Tests
Quiz.test.jsx	Question/answer rendering, checkbox selection, submit dialog, score display, error state, negative-marking warning
Assignment.test.jsx	Text/file submission fields, validation gating, API payload shape, success/error states
Certificate.test.jsx	Certificate content, QR code, optional logo, error fallback
CertificateForm.test.jsx	Validation, form submission, success alert, View Certificate link, API error