v0.0.1: Add Authentication Flow Example

Implements a complete authentication system with:
- Login/logout functionality with email and password
- Token storage and automatic refresh mechanism
- Secure keychain storage using actor-based concurrency
- Automatic token expiry monitoring with 30-second checks
- Comprehensive error handling for various auth scenarios
- Loading states for async operations
- Full test coverage with 12 passing tests

The example demonstrates advanced Store patterns including:
- Complex state management with authentication states
- Effect composition for async operations
- Dependency injection for testable services
- Actor-based storage for thread safety

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>