Standardize border radius tokens

[ramlal-01]

Description

Standardized border radius values across major UI components to ensure visual consistency and a more cohesive design system.

Fixes #4789

Motivation

Previously, cards, buttons, inputs, and modals used different border radius values, resulting in inconsistent UI styling. This change introduces a standardized radius scale and applies it across major components.

Type of change

• 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

Screenshots / Video (if applicable)

Add before/after screenshots showing the updated border radius styling across components.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my 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 run local unit tests using npm test and verified they pass
• I have run npm run lint and resolved any new errors or warnings
• I have verified responsiveness and visual alignment on desktop and mobile viewports

[ramlal-01]

Hi! I'd like to work on this issue. I've started implementing the border radius standardization and will submit a PR soon.

@SandeepVashishtha