[Migration] Migrate UI Components from Sass to PostCSS

[seanwuapps]

Objective

Migrate remaining UI components from Sass to PostCSS.

Components to Migrate

• go-accordion
• go-badge
• go-banner
• go-blockquote
• go-breadcrumbs
• go-tabs
• Other components identified during migration

For each component:

1. Create new .css file
2. Migrate styles maintaining current functionality
3. Update component's styleUrl
4. Verify styling and functionality
5. Update tests if necessary

Dependencies

• Blocked by [Migration] Replace Sass with PostCSS: Global Styles and Utils #278 (global styles migration)
• Can be worked on in parallel with [Migration] Migrate Form Components from Sass to PostCSS #279 (form components)

Testing Requirements

• Visual regression tests
• Cross-browser compatibility
• Responsive design verification
• Dark mode compatibility

Notes

• Prioritize components by usage/complexity
• Document any breaking changes
• Update component examples in documentation