- Create API client with auto-retry and token refresh support
- Add comprehensive API endpoints for tasks, tags, projects, sync, and auth
- Implement authStore for authentication state management
- Implement tasksStore with optimistic updates and offline queue
- Add derived stores for filtered task views (pending, completed, by project)
- Implement syncStore for managing sync state and queue
- Add client ID generation and persistence for sync tracking
- Add OAuth2 client for Authentik integration
- Implement JWT token generation and validation
- Add refresh token support with database storage
- Update database schema with oauth_subject, oauth_provider, and refresh_tokens table
- Create auth package with config, jwt, oauth, and token management
- Add OAuth endpoints: /auth/login, /auth/callback, /auth/refresh, /auth/logout
- Update AuthMiddleware to support both JWT and API key authentication
- Add user helper functions for OAuth user creation and retrieval
- Add .env.example with OAuth configuration template
API keys still work for CLI compatibility while JWT tokens support web/mobile clients.