Add authentication and API integration to samples app

[wendellmva]

Issue: Add authentication and API integration to samples app

Summary

Integrate authentication (login/logout) and connect the samples app to the Graph API and database, making all use cases work with real user data and live CRUD operations.

Goals

• Add login/logout functionality to samples app
• Integrate with Graph API authentication endpoints
• Connect use cases to real backend/database
• Enable authenticated CRUD operations
• Make app fully functional with real data

Scope

1. Authentication UI:
   • Add login page/component
   • Add logout functionality
   • Display user info when logged in
   • Add authentication state management
2. API Integration:
   • Create API client service
   • Configure API base URL (environment-based)
   • Implement JWT token storage/refresh
   • Add authorization headers to requests
3. Connect to GraphContext:
   • Wire up SPEC0200-0204 CRUD operations
   • Connect use cases to real data:
     • GitHub Issue tracker → real issues in graph
     • Kanban Board → real tasks/workflow
     • Todo List → real user todos
4. User Context:
   • Store authenticated user info
   • Filter data by logged-in user
   • Implement user-scoped operations

Acceptance Criteria

• Users can login with username/password
• JWT token stored and sent with API requests
• Users can logout and token is cleared
• Protected routes require authentication
• Use cases (GitHub Issue, Kanban, Todo) work with real user data
• CRUD operations persist to database via API
• User can only see/modify their own data
• Token refresh works when token expires
• Clear error messages for auth failures

Technical Implementation

1. AuthenticationService:
   • Login/logout methods
   • Token storage (localStorage/sessionStorage)
   • Token refresh logic
   • User state management
2. ApiClient Service:
   • Base HTTP client with auth headers
   • Methods for CRUD operations
   • Error handling
3. AuthenticationStateProvider:
   • Track authentication state
   • Provide user claims
4. Protected Routes:
   • Redirect to login when not authenticated
   • Show/hide UI based on auth state

API Endpoints Needed

• POST /api/auth/login
• POST /api/auth/logout
• POST /api/auth/refresh
• GET /api/auth/user
• CRUD endpoints for nodes, edges, types, properties

Checklist

• Create login page/component
• Implement AuthenticationService
• Add AuthenticationStateProvider
• Create ApiClient service
• Configure API base URL (appsettings)
• Implement token storage and refresh
• Add authorization to HTTP requests
• Connect GitHub Issue page to real API
• Connect Kanban Board to real API
• Connect Todo List to real API
• Add user-scoped data filtering
• Implement protected routes
• Add logout functionality
• Test full authentication flow
• Handle token expiration gracefully

Dependencies

• Issue Create Postgres migration for graph schema and identity storage #100: Database must be set up and migrated
• Graph API authentication endpoints must be available
• Issue Replace IdentityGraphContext with GraphContext-based identity storage #99: Graph-based identity storage

References

• Issue SPEC0210 - Samples App (WASM) for SPEC0200-0209 #97: Samples App (WASM)
• Issue Replace IdentityGraphContext with GraphContext-based identity storage #99: Graph-based identity storage
• SPEC0207: Authentication specification