- Introduced Web Crypto API polyfills (`@peculiar/webcrypto`) for Node.js to enable SSR-safe cryptography utilities.
- Added Jest setup file for global mocks (e.g., `localStorage`, `sessionStorage`, and `TextEncoder/Decoder`).
- Enhanced token validation behavior in `storage` tests to reject incomplete tokens.
- Replaced runtime configuration validation with clamping using `parseIntSafe` constraints for improved reliability.
- Updated `package.json` and `package-lock.json` to include new dependencies (`@peculiar/webcrypto` and related libraries).
- Centralized and refactored configuration management (`config`) with runtime validation for environment variables.
- Introduced utilities for secure token storage, including AES-GCM encryption and fallback handling.
- Enhanced `authStore` state management with token validation, secure persistence, and initialization from storage.
- Modularized authentication utilities and updated export structure for better maintainability.
- Improved error handling, input validation, and added detailed comments for enhanced clarity.
