feat: implement comments and activity panel in workspace

- Added CommentsPanel component for managing comments on documents.
- Integrated comment creation, deletion, and resolution functionalities.
- Implemented activity tracking for document interactions.
- Enhanced SketchPage with editing and saving capabilities.
- Introduced template management API endpoints for creating, sharing, and deleting templates.
- Added runtime validation report for frontend and backend.
- Created GettingStartedPanel for user onboarding with template options.
- Implemented Playwright E2E tests for accessibility and export functionality.

backend/requirements.txt

@@ -7,6 +7,7 @@ pydantic-settings==2.8.1
 python-jose[cryptography]==3.4.0
 bcrypt==4.2.1
 python-multipart==0.0.20
+httpx==0.28.1
 motor==3.7.0
 alembic==1.14.1
 email-validator==2.2.0