Feat/course and quiz improvements

[Robotron2]

Description

This PR implements the requested course UI and quiz features to improve the overall learning experience and accessibility.

Changes Made

• Course Card: Enhanced the course card component with enrollment status and progress indicators.
• Module List: Added completion tracking indicators, quiz availability badges, and estimated duration to the module list.
• Quiz Interface: Built an interactive, question-by-question quiz interface with progress tracking and submission handling.
• Results Screen: Created a comprehensive quiz results screen showing score, pass/fail status, per-question feedback, and context-aware next steps.
• Accessibility Improvements: Added ARIA labels and live regions (aria-live="polite" and aria-live="assertive") across the components to ensure screen readers correctly announce dynamic content and status changes.

Resolves Issues

Closes #257
Closes #258
Closes #259
Closes #260

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