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>

projects/auth-client/src/public-api.ts

@@ -0,0 +1,22 @@
+/*
+ * Public API Surface of auth-client
+ */
+
+// Models
+export * from './lib/models/auth.models';
+
+// Services
+export * from './lib/services/auth.service';
+export * from './lib/services/auth-http.service';
+export * from './lib/services/token.service';
+export * from './lib/services/oauth.service';
+
+// Guards
+export * from './lib/guards/auth.guard';
+export * from './lib/guards/guest.guard';
+
+// Interceptors
+export * from './lib/interceptors/auth.interceptor';
+
+// Legacy export for compatibility
+export * from './lib/auth-client';