Enhance download notifications and settings; add support for live activities

- Updated notification body to use proper German quotation marks for download failure alerts.
- Refactored audio interruption handling in PlayerEngine to utilize MainActor.assumeIsolated for better performance.
- Introduced nonisolated properties for support and downloads directories in ProgressSyncManager.
- Improved FullHistoryView and MainView with additional toolbar items and alerts for download failures.
- Added new toggles in SettingsView for parallel downloads and mobile data usage.
- Created new color assets for the DownloadWidgetExtension and updated widget appearance.
- Implemented Info.plist for DownloadWidgetExtension to support widget functionality.
- Enabled live activities support in iOS Info.plist.

ABS Client/DownloadWidgetExtension/Assets.xcassets/WidgetBackground.colorset/Contents.json

@@ -0,0 +1,20 @@
+{
+  "colors" : [
+    {
+      "color" : {
+        "color-space" : "srgb",
+        "components" : {
+          "alpha" : "1.000",
+          "blue" : "0.094",
+          "green" : "0.196",
+          "red" : "0.078"
+        }
+      },
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}