Filetree Feature and Performance Improvements

We improved the Filetree, a core element of the workspace, to make it more powerful and easier to use. This update focuses on increasing file management efficiency, securing visual clarity, and significantly boosting performance.

The key improvements are as follows:

• Multiselect: You can select multiple files at once using the Shift or Alt keys. You can perform batch operations such as moving, deleting, and opening tabs through drag and drop or the context menu.
• Improved visual hierarchy: Unnecessary gutters and icons have been removed to clearly distinguish between files and folders. Now, more intuitive navigation is possible through the Containment line, which indicates the hierarchical structure of folders.

In addition, we dramatically improved the loading and rendering performance of the filetree. We changed the loading sequence so that the file the user wants and its parent folders are loaded first, increasing loading speed for large filetrees.

This performance improvement is the result of completely refactoring the internal implementation of the filetree. We switched from the existing React Context-based state management to Jotai, which prevents unnecessary re-renders and allows state to be managed by separating it into small units called Atoms.