fix: improve mobile responsiveness for dashboard and sidebar

[SarthakKharche]

Summary

This PR improves mobile responsiveness and fixes UI/UX issues across the dashboard and related components. It ensures a smoother experience on smaller screens while also correcting authentication behavior on the landing page.

Type of Change

• Bug fix
• New feature
• UI / UX improvement
• Refactor
• Documentation
• Other

Related Issue

Closes #154

What was changed?

• Dashboard stat cards now stack vertically on smaller screens for better readability
• Improved responsive layout of dashboard components using proper breakpoints
• Fixed leaderboard overflow issue by enabling responsive scrolling / better layout handling
• Enhanced mobile experience for leaderboard (better alignment and usability)
• Fixed landing page auth button to correctly trigger GitHub OAuth
• Ensured /dev/login remains accessible for development/testing

Screenshots

Checklist

• My code follows the project structure and conventions
• I tested this locally (npm run dev)
• No hardcoded secrets or credentials
• I have updated documentation if needed

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Project	Deployment	Actions	Updated (UTC)
mergeship	Ready	Preview, Comment	May 22, 2026 2:27pm

[SarthakKharche]

@Coder-s-OG-s
Plz have a look