Add a Gists stat chip to the profile header

[Muragesh-24]

Summary

Added GitHub gist count support to the public profile header so users with public gists now see a linked N Gists chip.

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closes #212

Type of Change

• Bug fix
• New feature
• Documentation update
• Refactor / code cleanup

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Changes Made

• Fetched public_gists from the GitHub REST GET /users/{username} endpoint
• Added publicGists to the public profile data model
• Rendered a conditional gist chip in the public profile header
• Linked the chip to the user's GitHub gists page
• Added unit tests for the new gist fetch helper

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How to Test

Steps for the reviewer to verify this works:

1. Open a public profile with at least one public gist
2. Verify a N Gists chip appears in the header
3. Click the chip and confirm it opens the user's GitHub gists page
4. Open a profile with zero public gists and confirm the chip is hidden

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Checklist

• Linked issue in summary
• npm run lint passes locally
• No TypeScript errors (npm run type-check)
• Self-reviewed the diff
• Added/updated tests if applicable

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Accessibility Checklist

• Keyboard navigation works for the gist chip link
• The link has a clear destination
• The chip remains hidden when not applicable

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Additional Notes

The gist chip is only shown when public_gists > 0 to keep the header clean for users without public gists.

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[github-actions]

GSSoC Label Checklist 🏷️

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