feat: Implement PUT endpoint and UI for question editing

[thaivinhle]

Description

Summary of work:

• Implemented the PUT /courses/:course_id/questions/:question_id API endpoint in core/.
• Implemented the updateQuestion function and dispatched the updateQuestionInLecture Redux action in SingleQuestionTeacher.jsx.
• Fixed the build failure by defining the updateQuestionInLecture Redux action.
• Resolved navigation bug in QuestionCard.jsx to allow access to the edit form.

Fixes #366

Checklist:

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• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
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[LaserBread]

I'm not sure why you removed the {!sectionId && ( part. Was something wrong with this?

[thaivinhle]

The {!sectionId && ...} conditional was preventing the "View/Edit Question" button from appearing when teachers viewed questions in a section context (URL: /sections/:sectionId/lectures/:lectureId).

This meant teachers could only edit questions when viewing them at the course level, not from within sections. Since editing a question is a course-level operation (the backend PUT endpoint is /courses/:courseId/questions/:questionId and doesn't require a sectionId), teachers should be able to edit questions regardless of where they're viewing them from.

The fix removes this conditional so the edit button is always visible to teachers, while keeping the section-specific "Publish Question" toggle properly gated behind {sectionId && props.lecturePublished && ...}.

This way we maintain proper separation of concerns: editing is always available (course-level operation), while publishing is only available in the appropriate context (section-specific operation).

[LaserBread]

I see. That's good.

[LaserBread]

Most of the code looks very good. However, would you mind adding some test cases for your core/app/api/questions.js? I can totally help if you need it.

Also check my comment in the commit