Save the intended destination to sessionStorage before navigating to
the OAuth provider, and read it back in AuthCallback after login.
Also handles 401-triggered redirects so session-expired users are
returned to the page they were on.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Added ShareModal component to manage user and link sharing for documents.
- Created AuthContext to handle user authentication state and token management.
- Updated useYjsDocument hook to support sharing via tokens.
- Enhanced Yjs document creation to include user information and authentication tokens.
- Introduced AuthCallback page to handle authentication redirects and token processing.
- Modified EditorPage and KanbanPage to include share functionality.
- Created LoginPage with Google and GitHub authentication options.
- Added styles for LoginPage.
- Defined types for authentication and sharing in respective TypeScript files.
