Build a component that displays files and directories in a hierarchical tree format.

Requirements:

1. Display names of files and directories.
2. Directories:
   • Can contain other directories and files.
   • Should be expandable and collapsible by clicking on them.
   • Should be displayed before files and sorted alphabetically.
   • Can be empty.
3. Files:
   • Are leaf nodes, cannot be expanded or interacted with.
4. Indent contents to visually represent hierarchy.
5. Focus on functionality over styling.
6. The component should work out-of-the-box in a live React preview (e.g., CodeSandbox/Sandpack).