Refresh Files list automatically when an upload finishes

Uploads run entirely in ShareUploadService.kt, an Android foreground
service with no channel back to Dart once started - by design, so
closing the app mid-upload doesn't interrupt it. That meant
FilesController had no way to know a batch had finished, so a newly
uploaded file only appeared after a manual pull-to-refresh.

Adds a one-shot completion signal instead of a full stream: the
service publishes into a new UploadEventBus (in-process pub/sub,
mirroring SyncStatusBus) once a batch finishes with at least one
success, MainActivity forwards it to Dart over a new
dev.ayushya.noo/upload_service/status EventChannel, and
FilesController (subscribed in its own constructor, same pattern
OfflineController already uses for sync completion) calls
refreshData() when the event's destination folder matches
currentFolderPath. Covers both upload entry points (share-to-Noo and
Files' own "+" -> Upload file), since they already share the same
ShareUploadView/UploadService path.

Move/Copy needed no fix - ItemOperations already calls
files.invalidateCache() + refreshData() on success.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

lib/services/upload_service.dart

@@ -5,6 +5,27 @@ import '../providers/session_controller.dart';
 import 'native_channel.dart';
 import 'share_intent_service.dart';
 
+/// One upload batch finishing - see [UploadService.completions].
+class UploadCompletion {
+  final String remoteFolder;
+  final int succeeded;
+  final int failed;
+
+  const UploadCompletion({
+    required this.remoteFolder,
+    required this.succeeded,
+    required this.failed,
+  });
+
+  factory UploadCompletion.fromMap(Map<dynamic, dynamic> map) {
+    return UploadCompletion(
+      remoteFolder: map['remoteFolder'] as String? ?? '/',
+      succeeded: (map['succeeded'] as num?)?.toInt() ?? 0,
+      failed: (map['failed'] as num?)?.toInt() ?? 0,
+    );
+  }
+}
+
 /// Hands a "Share to Noo" upload off to `ShareUploadService.kt`'s Android
 /// foreground service, which does the actual prepare+upload entirely on its
 /// own from there - including surviving the app being closed - with a
@@ -14,11 +35,15 @@ import 'share_intent_service.dart';
 /// real Android Service does.
 class UploadService {
   static const _channel = MethodChannel('dev.ayushya.noo/upload_service');
+  static const _statusChannel = EventChannel(
+    'dev.ayushya.noo/upload_service/status',
+  );
 
   /// Starts uploading [files] into the active account's current folder.
   /// Fire-and-forget from Dart's perspective - once this returns, the
   /// service owns the rest and reports progress/completion/cancellation
-  /// through its own notification, not back to the app.
+  /// through its own notification, not back to the app. [completions] is
+  /// the one thing it does report back, for `FilesController` to act on.
   static Future<void> startUpload(
     SessionController session,
     FilesController files,
@@ -37,4 +62,15 @@ class UploadService {
       'remoteFolder': files.currentFolderPath,
     });
   }
+
+  /// Fires once per finished batch (at least one file uploaded) from
+  /// `UploadEventBus` (Kotlin) - lets `FilesController` refresh the
+  /// destination folder if it's the one currently on screen, instead of the
+  /// list only updating on a manual pull-to-refresh. One shared stream,
+  /// deliberately: see `SyncService.statusStream`'s identical doc comment -
+  /// `EventChannel.receiveBroadcastStream()` opens its own native
+  /// subscription per call, and the native side only keeps the latest one.
+  static final Stream<UploadCompletion> completions = _statusChannel
+      .receiveBroadcastStream()
+      .map((event) => UploadCompletion.fromMap(event as Map<dynamic, dynamic>));
 }