feat: add green sparkle cursor effect to diease page

[Muskankr]

Which issue does this PR close?

• Closes Disease Predictor page layout is broken (Navbar, Logo, and Main Content not working properly) #928

Rationale for this change

The disease.html page previously had a static cursor with no visual feedback.
Adding a sparkle cursor improves interactivity and provides a more engaging user experience, aligning with AgriTech’s modern UI/UX goals.

What changes are included in this PR?

• Implemented a green sparkle cursor effect that follows the mouse pointer.
• Added CSS for thicker sparkles (20px) with smooth fade‑out animation.
• Integrated JavaScript to dynamically generate and remove sparkles on mouse movement.
• Scoped changes to disease.html and disease.css only.

Screenshots

Before

After

Are these changes tested?

• ✅ Tested locally in light theme.
• ✅ Verified sparkles appear consistently across desktop and mobile browsers.
• ✅ Confirmed sparkles last longer (1.5s) for visibility and screenshots.
• ❌ No backend/API changes required.

Are there any user-facing changes?

Yes. Users will now see a green sparkle trail following their cursor on the disease.html page.
This is a purely visual enhancement and does not affect functionality.

Thank you reviewing my PR!

Disease predictor page is already fixed so i added sparkle cursor effect instead of that.

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[github-actions]

Thanks for creating a PR for your Issue! ☺️

We'll review it as soon as possible.
In the meantime, please double-check the file changes and ensure that all commits are accurate.

If there are any unresolved review comments, feel free to resolve them. 🙌🏼

[github-actions]

🎉 Congrats @Muskankr on getting your PR merged! 🙌
Thanks for the contribution — looking forward to more from you 🚀