Introduced consistent Loading, Error and Empty states across Dashboard, Leaderboard and Challenge views

[Yashvi29-power]

Team Number : Team 125

Description
This PR improves UI feedback and interaction clarity across the Code Duel frontend by introducing consistent Loading, Error, and Empty states. Skeleton components are used during async operations, while EmptyState provides clear messaging when data is unavailable or fails to load. The goal is to enhance perceived performance and maintain visual consistency without modifying existing business logic.

Related Issue
Closes #65

Type of Change
☐ Bug fix
☐ New feature
☐ Breaking change
☐ Documentation update
☐ Code refactoring
☐ Performance improvement
☑ Style/UI improvement

Changes Made

• Added Skeleton loading states for Dashboard, Leaderboard, and Challenge views
• Introduced minimal error UI using existing EmptyState component
• Standardized empty data feedback across major pages
• Maintained existing design system and Tailwind styling
• Ensured no changes to API logic, routing, or authentication flow

Testing
☑ Tested on Desktop
☑ No console errors during navigation
☑ Application builds successfully

Additional Notes
This PR focuses strictly on UI/UX enhancements. Existing architecture, API integrations, and data models remain unchanged to ensure safe integration with the current codebase.

SCREENSHOTS ARE NOT ATTACHED AS WAS NOT ABLE TO GET ACCESS TO THE DASHBOARD OF THE WEBSITE AND THERE WERE SOME BACKEND ISSUES. GOOD AT FRONTEND, SO FOCUSED ON THAT

[krishnapaljadeja]

✅ PR Validation Passed

Hey @Yashvi29-power! Your PR looks good. Here is what we found:

Field	Value
Team Number	Team 125
Linked Issue	Closes #65

A maintainer will review your PR within 24–48 hours. Stay responsive to feedback!

GDG CHARUSAT Open Source Contri Sprintathon

[aaleya5]

the skeleton components need to be merged into the pages.
also, take a pull from main and then make changes so as to resolve merge conflicts.
@Yashvi29-power

[aaleya5]

please resolve conflicts

[aaleya5]

@Yashvi29-power please atleast run the project before committing. there are multiple errors that are not there previously in my main branch. the project doesnt even run if i merge your pull request.
run it when you resolve the merge conflicts so that if something goes haywire, you can test it out.

[Yashvi29-power]

working on it

[aaleya5]

hey @Yashvi29-power the errors are syntactical errors that arose when you resolved your merge conflicts.
run this project and resolve them before commit.

[aaleya5]

@Yashvi29-power are you going to work on this? confirm within an hour.

[Yashvi29-power]

I was working on it but not able to resolve it