feat: revamped `@asgardeo/react` SDK

[brionmario]

Is your feature request related to a problem? Please describe.
The current @asgardeo/react SDK is optimized primarily for redirect-based flows and includes many IAM-specific abstractions, which introduces friction for frontend developers unfamiliar with such concepts. Configuration can be verbose, and developer experience (DX) suffers in modern app frameworks like Next.js and Vite, especially in App Router or client/server hybrid scenarios.

Describe the solution you would prefer
We're proposing a complete revamp of the SDK with the following goals:

• ✅ Dual flow support: Support both redirect-based and in-app/native (popup/token exchange) login flows.
• ✅ Minimal configuration: Smart defaults with the option to override, ideal for quick integration.
• ✅ Improved DX: Provide intuitive, developer-friendly APIs with minimal IAM jargon.
• ✅ Drop-in components: Include prebuilt, customizable React components (e.g., SignInButton, UserAvatar, AuthProvider) to help devs get started fast.
• ✅ First-class framework support: Out-of-the-box compatibility with Next.js App Router, Vite, and traditional React setups.
• ✅ Separation of client/server concerns: Enable modular imports like import { useAuth } from "@asgardeo/react/client" to preserve use client directive support.

Additional context
This revamp will help frontend teams:

• Integrate secure authentication faster without deep IAM knowledge.
• Avoid common issues in hybrid rendering environments.
• Improve overall maintainability and testability of their authentication flows.

This update also positions @asgardeo/react to be a modern, DX-focused alternative to libraries like auth0-react or next-auth for organizations seeking an enterprise IAM backend with frontend simplicity.