[BUG] Remove dead code from quiz component

[deepanshusingla076]

Describe the bug
The quiz explanation feature never appears after completing a quiz. The quizCompleted variable in quiz.jsx is always set to false, so the explanation section is never shown, even when the quiz is finished.

To Reproduce
Steps to reproduce the behavior:

1. Go to the Interview Quiz page
2. Start and complete a quiz
3. Try to view the explanation for any question
4. The explanation section does not appear

Expected behavior
After finishing the quiz, I expect to see the explanation for each question, but it never shows up.

Device (please complete the following information):

• Device Type: Desktop
• OS: Windows11
• Browser chrome

Additional context
The bug is in quiz.jsx :
const quizCompleted = false; // This never changes!
Because of this, the explanation UI is always hidden.
I think the logic for tracking quiz completion needs to be fixed so users can see explanations after finishing the quiz.

[github-actions]

Thank you for raising this issue!

We'll review it as soon as possible. We truly appreciate your contributions! ✨

Meanwhile make sure you've visited the README.md, CONTRIBUTING.md, and CODE_OF_CONDUCT.md before creating a PR for this. Also, please do NOT create a PR until this issue has been assigned to you. 😊

[arunkumar-201]

Hi @deepanshusingla076,

I am a GSSoC 2026 contributor and would like to work on this issue.

I reviewed the bug description and understand that the explanation section never appears because the quizCompleted state is not being updated correctly. I would like to investigate the quiz completion flow, implement the proper state handling, and ensure explanations are displayed after a quiz is completed.

Could you please assign this issue to me?

Thank you!