fix: add email validation during account registration

[kumud-05]

📝 Pull Request Description

Related Issue

Closes #343

Summary

This PR fixes the missing email validation during account registration by implementing validation on both the frontend and backend. It also improves the user experience by clearing the email validation error once a valid email address is entered.

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Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature
• ♻️ Refactoring
• 📝 Documentation update
• 🎨 UI/UX improvement
• 🔥 Other (please describe) ______

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How Has This Been Tested?

• Tested registration with invalid email formats (e.g., abc, abc@gmail, K@gbjsd.comhbj45) to verify that appropriate validation errors are displayed.
• Verified that the email validation error is cleared immediately after entering a valid email address.
• Confirmed that backend validation prevents account creation with invalid email formats.

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Screenshots (if applicable)

Before

• Invalid email addresses were accepted without proper validation.

After

• Invalid email addresses display a validation error.
• Email validation errors disappear immediately after entering a valid email.
• Backend rejects invalid email formats even if frontend validation is bypassed.

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Checklist

• My code follows the project's guidelines
• I have tested my changes
• I have updated documentation where necessary (Not required)
• I have linked the related issue
• My changes do not introduce new warnings or errors

[kumud-05]

Hi @KaranUnique , could you please review this PR when you have a chance? This fixes the assigned issue by implementing email validation on both the frontend and backend, along with improving the validation behavior. I'd appreciate your feedback. Thank you!