chore: trim redundant comments

lib/services/platform_bridge.dart

@@ -865,10 +865,7 @@ class PlatformBridge {
     return result as bool;
   }
 
-  /// iOS only: mark that a download queue is active so the app keeps in-flight
-  /// downloads running for a short window whenever it is backgrounded. iOS
-  /// grants a limited budget (roughly 30s on modern versions) per background
-  /// entry; there is no foreground-service equivalent, so this is best-effort.
+  /// iOS only: keep in-flight downloads running briefly after backgrounding.
   static Future<void> beginBackgroundDownloadTask() async {
     if (!Platform.isIOS) return;
     try {
@@ -876,8 +873,7 @@ class PlatformBridge {
     } catch (_) {}
   }
 
-  /// iOS only: mark that the download queue is no longer active (queue finished
-  /// or paused), stopping background-time extension.
+  /// iOS only: stop the background-time extension (queue finished or paused).
   static Future<void> endBackgroundDownloadTask() async {
     if (!Platform.isIOS) return;
     try {