Refactor prefetch_project_files function for improved readability

- Simplified the iteration over directory entries in the `prefetch_project_files` function by using `into_iter().flatten()` instead of a nested loop.
- This change enhances code clarity while maintaining the existing functionality of collecting valid directory entries.

These modifications aim to streamline the code and improve maintainability in the prefetching process.

src/serve_session.rs

@@ -152,12 +152,10 @@ fn prefetch_project_files(project: &Project) -> io::Result<PrefetchCache> {
         if !root.exists() {
             continue;
         }
-        for entry in WalkDir::new(root).follow_links(true) {
-            if let Ok(e) = entry {
+        for e in WalkDir::new(root).follow_links(true).into_iter().flatten() {
             entries.push(e);
         }
     }
-    }
 
     // Also include the project file itself (read by project middleware).
     if let Ok(meta) = std::fs::metadata(&project.file_location) {

src/snapshot_middleware/dir.rs

@@ -472,7 +472,7 @@ mod test {
         .unwrap();
 
         fn count_nodes(snap: &InstanceSnapshot) -> usize {
-            1 + snap.children.iter().map(|c| count_nodes(c)).sum::<usize>()
+            1 + snap.children.iter().map(count_nodes).sum::<usize>()
         }
         let total = count_nodes(&snap);
         assert!(total > 100, "Should have many nodes, got {total}");