API Integration for frontend

[codebestia]

Description

This PR replaces all static mock data with real backend API integration across the entire frontend. It implements a robust data fetching layer using React Query and Axios, ensuring proper loading states, error handling, and caching.

Closes #185

Solana Wallet for Payout

Wallet: 4QhseKvBuaCQhdkP248iXoUxohPzVC5m8pE9hAv4nMYw

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update
• 🎨 Style/UI update
• ♻️ Code refactoring
• ⚡ Performance improvement
• ✅ Test addition/update

Checklist

• Code is clean and follows the issue spec exactly
• One PR per bounty (no multiple bounties in one PR)
• All existing tests pass
• No console.log or debugging code left behind
• No hardcoded secrets or API keys

Testing

• Manual testing performed
• Unit tests added/updated
• Integration tests added/updated

Additional Notes

• The VITE_API_URL environment variable should be set in the frontend .env file for production deployment.
• Reusable Skeleton components from common/Skeleton.tsx were used to improve perceived performance.

[github-actions]

Automated review: changes requested (see comment)