Add auth-client library for Elixir auth service integration

- Complete Angular client library for authentication and authorization
- JWT token management with automatic refresh and storage
- OAuth integration with social providers (Google, GitHub, etc.)
- Two-factor authentication support (TOTP and backup codes)
- Route guards for authentication and scope-based authorization
- HTTP interceptor for automatic token injection and refresh
- Comprehensive TypeScript interfaces for all API models
- User management features (profile updates, password changes)
- Cross-tab synchronization and token validation
- Complete usage guide with practical examples

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

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

.claude/settings.local.json

@@ -0,0 +1,10 @@
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