Make Signup Page Fully Interactive and Seamless

[noel-mugisha]

Improve the signup workflow to be fully interactive and seamless for users:

• Add interactive JavaScript so users can toggle password visibility for both password and confirm password fields.
• Implement real-time password strength indicator, password match check, and visual feedback.
• Make role selection visually clear and easy to select, with interactive highlighting.
• Ensure form validation and error/success feedback are consistent and visible.
• Make sure the signup experience matches the style and usability of the login page.
• All features should work smoothly on desktop and mobile.

Label: enhancement