Refactor unused imports in studio.rs and fs_snapshot.rs for cleaner code

- Removed unnecessary imports from `studio.rs` and `fs_snapshot.rs`, streamlining the code and improving readability.
- This cleanup enhances maintainability by reducing clutter and focusing on essential dependencies.

src/syncback/fs_snapshot.rs

@@ -3,8 +3,6 @@ use std::{
     io,
     path::{Path, PathBuf},
     sync::atomic::{AtomicUsize, Ordering},
-    thread,
-    time::Duration,
 };
 
 use memofs::Vfs;