Make auth UI in urbackend/react configurable

[Nitin-kumar-yadav1307]

Description

The current authentication UI in urbackend/react is too hardcoded. It would be better if the SDK allowed basic branding and login flow customization instead of forcing a fixed setup.

Problems Observed

• Authentication method selection is not customizable.
• Users cannot restrict the app to only GitHub login.
• Users cannot restrict the app to only Google login.
• Users cannot use email/password only and bypass social login.
• The UI colors are not customizable.
• The login/sign-up pages do not allow showing a custom brand name.

Expected Behavior

The SDK should allow developers to:

• Enable or disable GitHub login independently.
• Enable or disable Google login independently.
• Enable or disable email/password authentication independently.
• Customize theme colors used in the authentication UI.
• Pass a custom brand name, logo, or application title for login and sign-up screens.
• Override default labels and text shown on authentication pages.
• Keep sensible defaults while allowing customization when needed.

Why This Matters

Most applications require at least basic white-label support. The current authentication experience feels locked to a single design and a fixed set of login providers, making the SDK less flexible for real-world projects and harder to adopt in production environments.

Suggested Enhancement

Add configuration options to the React SDK for:

• Enabled authentication providers
• Email/password-only mode
• Theme customization (colors, branding)
• Brand name and logo support
• Custom authentication page labels and text

Example API (Conceptual)

<AuthProvider
  providers={{
    github: true,
    google: false,
    emailPassword: true,
  }}
  branding={{
    appName: "My App",
    logo: "/logo.png",
    primaryColor: "#4F46E5",
  }}
  labels={{
    signInTitle: "Welcome Back",
    signUpTitle: "Create Your Account",
  }}
/>

This would provide a more flexible, white-label authentication experience while maintaining backward compatibility through default settings.

[Nitin-kumar-yadav1307]

@yash-pouranik