* feat(tests): add Jest configuration and setup for testing environment
- Introduced Jest configuration file to set up testing environment with TypeScript support and JSDOM.
- Added setupTests.ts for global test configurations, including mocks for ResizeObserver and IntersectionObserver.
- Updated package.json and package-lock.json to include Jest and related dependencies.
- Implemented utility functions for processing markdown content, including handling tables and <think> tags.
- Added comprehensive tests for markdown utility functions to ensure proper functionality.
* refactor(makefile): separate frontend commands into a dedicated Makefile
- Removed frontend-related targets from the main Makefile and created a new Makefile.frontend to manage frontend-specific commands.
- Updated the main Makefile to include a reference to the new frontend Makefile and added a help message for frontend commands.
- This restructuring improves organization and clarity for managing backend and frontend build processes.
