Fix file descriptor leak in DirectoryWatcher (#1104)

- `DirectoryWatcher` opens file descriptors for monitoring
  directories but never closes them, causing a file descriptor
  leak.
- Adds `setCancelHandler` to properly close file descriptors
  when the `DispatchSource` is cancelled.

Signed-off-by: Ronit Sabhaya <ronitsabhaya75@gmail.com>

Sources/Helpers/APIServer/DirectoryWatcher.swift

@@ -48,13 +48,18 @@ public class DirectoryWatcher {
 
         let descriptor = open(directoryURL.path, O_EVTONLY)
 
-        source = DispatchSource.makeFileSystemObjectSource(
+        let dispatchSource = DispatchSource.makeFileSystemObjectSource(
             fileDescriptor: descriptor,
             eventMask: .write,
             queue: monitorQueue
         )
 
-        source?.setEventHandler { [weak self] in
+        // Close the file descriptor when the source is cancelled
+        dispatchSource.setCancelHandler {
+            close(descriptor)
+        }
+
+        dispatchSource.setEventHandler { [weak self] in
             guard let self else { return }
 
             do {
@@ -65,7 +70,8 @@ public class DirectoryWatcher {
             }
         }
 
-        source?.resume()
+        source = dispatchSource
+        dispatchSource.resume()
     }
 
     deinit {