feat: download queue enhancement

flo/AlbumView.swift

···
     .toolbar {
       if !isDownloadScreen {
         DownloadButton(
-          isDownloading: downloadViewModel.isDownloading(),
+          isDownloading: downloadViewModel.isDownloading(viewModel.album.name),
           isDownloaded: viewModel.isDownloaded,
           progress: downloadViewModel.getDownloadedTrackProgress(albumName: viewModel.album.name)
             / 100
···
           if viewModel.isDownloaded {
             showDeleteAlbumAlert.toggle()
           } else {
-            if downloadViewModel.isDownloading() {
+            if downloadViewModel.isDownloading(viewModel.album.name) {
               downloadViewModel.cancelCurrentAlbumDownload(albumName: viewModel.album.name)
             } else {
               viewModel.downloadAlbum(viewModel.album)

flo/DownloadButtonView.swift

···
           Circle()
             .trim(from: 0, to: 1)
             .stroke(
-              isDownloading ? Color.gray.opacity(0.2) : Color("PlayerColor"),
+              isDownloading ? Color.gray.opacity(0.2) : Color(.accent),
               style: StrokeStyle(lineWidth: 1.5)
             )
             .overlay(
               Circle()
                 .trim(from: 0, to: displayProgress)
-                .stroke(Color("PlayerColor"), style: StrokeStyle(lineWidth: 1.5, lineCap: .round))
+                .stroke(Color(.accent), style: StrokeStyle(lineWidth: 1.5, lineCap: .round))
             )
 
           Image(systemName: isDownloading ? "stop.fill" : "arrow.down")
             .resizable()
             .scaledToFit()
-            .padding(3.5)
+            .padding(4)
             .frame(width: 17, height: 17)
+            .font(.system(size: 17, weight: .bold))
         }
       }
       .frame(width: 21, height: 21)

flo/DownloadViewModel.swift

···
 
   private var activeDownloads: [String: DownloadRequest] = [:]
 
-  func isDownloading() -> Bool {
+  func isDownloading(_ albumName: String) -> Bool {
     return downloadItems.filter({ $0.status == .downloading }).count > 0
+      && downloadItems.filter({ $0.album == albumName }).count > 0
   }
 
   func getRemainingDownloadItems() -> Int {
···
   }
 
   private func startDownload(index: Int) {
+    var hasPassedThreshold = false
+
     let item = downloadItems[index]
 
     guard item.status != .downloading && item.status != .completed else { return }
 
     currentDownloads.insert(item.id)
 
-    var hasPassedThreshold = false
-
     let progressUpdate: (Double) -> Void = { progress in
       self.updateItemProgress(itemId: item.id, progress: progress)
 
···
           }
         }
 
-        activeDownloads[item.id] = downloadRequest
+        await MainActor.run {
+          activeDownloads[item.id] = downloadRequest
+        }
       }
     }
   }