refactor: improve write_todos tool and UI components

- Refactored the write_todos tool to enhance argument and result schemas using Zod for better validation and type safety.
- Updated the WriteTodosToolUI to streamline the rendering logic and improve loading states, ensuring a smoother user experience.
- Enhanced the Plan and TodoItem components to better handle streaming states and display progress, providing clearer feedback during task management.
- Cleaned up code formatting and structure for improved readability and maintainability.

surfsense_web/components/tool-ui/shared/index.ts

@@ -1,3 +1,2 @@
 export * from "./schema";
 export * from "./action-buttons";
-