💡 [Feature]: Add basic trigonometric functions to calculator

[madhavcodes25]

❓ Problem Statement

Current calculator lacks basic trigometric functions

🚀 Proposed Enhancement

Add basic trigometric functions to the calculator

🛠️ Suggested Implementation

Add working buttons for sin, cos and tan on the calculator with proper error handling.

• I am a registered GSSoC 2026 contributor.
• I would like to implement this feature myself.

[github-actions]

⚠️ Important Contribution Guideline

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1. Comment on this issue to express interest
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3. Once assigned, you can start working on the PR
4. Include the assignment in your PR checklist

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[Vanshikakhasat]

/assign gssoc

[Vanshikakhasat]

I would like to work on this issue. Please assign it to me.