fix: local sync task never runs on iOS (#21491)

* fix: local sync task never runs on iOS

* chore: rename ios register method

* refactor from using dart callback to dart entrypoint + more logs

* check if file exists before hashing

* reschedule local sync task

* chore: rename background worker logger

* refactor: move file exists check inside repo

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

mobile/lib/platform/background_worker_api.g.dart

@@ -82,7 +82,7 @@ class BackgroundWorkerFgHostApi {
     }
   }
 
-  Future<void> enableUploadWorker(int callbackHandle) async {
+  Future<void> enableUploadWorker() async {
     final String pigeonVar_channelName =
         'dev.flutter.pigeon.immich_mobile.BackgroundWorkerFgHostApi.enableUploadWorker$pigeonVar_messageChannelSuffix';
     final BasicMessageChannel<Object?> pigeonVar_channel = BasicMessageChannel<Object?>(
@@ -90,7 +90,7 @@ class BackgroundWorkerFgHostApi {
       pigeonChannelCodec,
       binaryMessenger: pigeonVar_binaryMessenger,
     );
-    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(<Object?>[callbackHandle]);
+    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(null);
     final List<Object?>? pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
     if (pigeonVar_replyList == null) {
       throw _createConnectionError(pigeonVar_channelName);
@@ -164,6 +164,29 @@ class BackgroundWorkerBgHostApi {
       return;
     }
   }
+
+  Future<void> close() async {
+    final String pigeonVar_channelName =
+        'dev.flutter.pigeon.immich_mobile.BackgroundWorkerBgHostApi.close$pigeonVar_messageChannelSuffix';
+    final BasicMessageChannel<Object?> pigeonVar_channel = BasicMessageChannel<Object?>(
+      pigeonVar_channelName,
+      pigeonChannelCodec,
+      binaryMessenger: pigeonVar_binaryMessenger,
+    );
+    final Future<Object?> pigeonVar_sendFuture = pigeonVar_channel.send(null);
+    final List<Object?>? pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
+    if (pigeonVar_replyList == null) {
+      throw _createConnectionError(pigeonVar_channelName);
+    } else if (pigeonVar_replyList.length > 1) {
+      throw PlatformException(
+        code: pigeonVar_replyList[0]! as String,
+        message: pigeonVar_replyList[1] as String?,
+        details: pigeonVar_replyList[2],
+      );
+    } else {
+      return;
+    }
+  }
 }
 
 abstract class BackgroundWorkerFlutterApi {