Xumm OAuth2 PKCE Client SDK

The `xumm-oauth2-pkce` JavaScript SDK facilitates client-side only OAuth2 Authorization Code with PKCE (Proof Key for Code Exchange) flow for the Xumm ecosystem. Currently at version 2.8.7, this package provides a secure method for web applications to authenticate users with Xumm without requiring a backend server for token exchange. It is actively maintained and typically follows a release cadence tied to Xumm ecosystem updates. Key differentiators include its focus on client-side security via PKCE, out-of-the-box handling of browser redirects and session persistence (using `localStorage` by default), and offering both event-driven and promise-based APIs. It integrates seamlessly into browser environments, abstracting away the complexities of the OAuth2 PKCE flow for Xumm users, and ships with TypeScript types for enhanced development experience.