Improve register route

[Chayan8837]

Description

This PR addresses issue, where registration was being allowed for the same email address multiple times on the client-side. However, due to constraints in the database, only the first registration was accepted. This fix resolves the issue by ensuring the client-side handles this scenario asynchronously, preventing multiple submissions of the same email.

Fixes #156

Type of change

• improve the endpoints with better error handling
• client side code improvement

Screencast.from.2025-02-23.16-53-12.mp4

now its working properly

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Test Configuration:

• Firmware version:
• Hardware:
• Toolchain:
• SDK:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules