simplified code across the app and consolidated duplicated helpers

lib/utils/downloads/download_job.dart

@@ -35,11 +35,7 @@ class DownloadFailed extends DownloadStatus {
 /// the same job. Kept engine-agnostic on purpose — the native
 /// `background_downloader` task lives entirely inside [DownloadManager].
 class DownloadJob {
-  DownloadJob({
-    required this.remotePath,
-    required this.name,
-    this.remoteFile,
-  });
+  DownloadJob({required this.remotePath, required this.name, this.remoteFile});
 
   final String remotePath;
   final String name;
@@ -59,10 +55,7 @@ class DownloadJob {
     const DownloadInProgress(0),
   );
 
-  bool get isFinished =>
-      status.value is DownloadDone ||
-      status.value is DownloadFailed ||
-      status.value is DownloadCancelled;
+  bool get isFinished => status.value is! DownloadInProgress;
 
   bool get isDone => status.value is DownloadDone;
   bool get isFailed => status.value is DownloadFailed;

lib/utils/downloads/download_manager.dart

@@ -237,9 +237,7 @@ class DownloadManager {
         // instead of freezing at the last percent.
         job.status.value = const DownloadCancelled();
       }
-      _jobs.remove(job.remotePath);
-      if (taskId != null) _byTaskId.remove(taskId);
-      scheduleMicrotask(job.dispose);
+      _forget(job);
     }
     _refreshVisible();
   }
@@ -330,10 +328,14 @@ class DownloadManager {
   // --- bookkeeping -----------------------------------------------------------
 
   void _remove(DownloadJob job) {
+    _forget(job);
+    _refreshVisible();
+  }
+
+  void _forget(DownloadJob job) {
     _jobs.remove(job.remotePath);
     final taskId = job.taskId;
     if (taskId != null) _byTaskId.remove(taskId);
-    _refreshVisible();
     scheduleMicrotask(job.dispose);
   }
 

lib/utils/file_clipboard.dart

@@ -21,16 +21,15 @@ class FileClipboard extends ChangeNotifier {
   List<CacheableFile> get files => List.unmodifiable(_files);
   bool get isEmpty => _files.isEmpty;
 
-  void cut(List<CacheableFile> files) {
-    if (files.isEmpty) return;
-    _operation = FileClipboardOperation.cut;
-    _files = List.of(files);
-    notifyListeners();
-  }
+  void cut(List<CacheableFile> files) =>
+      _set(FileClipboardOperation.cut, files);
 
-  void copy(List<CacheableFile> files) {
+  void copy(List<CacheableFile> files) =>
+      _set(FileClipboardOperation.copy, files);
+
+  void _set(FileClipboardOperation operation, List<CacheableFile> files) {
     if (files.isEmpty) return;
-    _operation = FileClipboardOperation.copy;
+    _operation = operation;
     _files = List.of(files);
     notifyListeners();
   }

lib/utils/random_id.dart

@@ -8,12 +8,3 @@ String randomHexId({int bytes = 16}) {
     (_) => random.nextInt(256),
   ).map((b) => b.toRadixString(16).padLeft(2, '0')).join();
 }
-
-/// Random RFC 4122 version-4 UUID, for ids a server expects in UUID form.
-String randomUuidV4() {
-  final hex = randomHexId();
-  final variant = (int.parse(hex[16], radix: 16) & 0x3 | 0x8).toRadixString(16);
-  return '${hex.substring(0, 8)}-${hex.substring(8, 12)}-'
-      '4${hex.substring(13, 16)}-$variant${hex.substring(17, 20)}-'
-      '${hex.substring(20)}';
-}