fix(bt): honor selected files when creating resolved tasks

ui/flutter/test/features/tasks/domain/task_record_test.dart

@@ -0,0 +1,44 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:gopeed/api/model/task.dart' as api;
+import 'package:gopeed/features/tasks/domain/task_record.dart';
+
+void main() {
+  api.Task buildTask(List<int> selection, int size) => api.Task.fromJson({
+    'id': 'bt-selection',
+    'name': 'bundle',
+    'protocol': 'bt',
+    'status': 'running',
+    'uploading': false,
+    'createdAt': '2026-01-01T00:00:00Z',
+    'updatedAt': '2026-01-01T00:00:00Z',
+    'meta': {
+      'req': {'url': 'magnet:?xt=urn:btih:test'},
+      'opts': {'path': '/downloads', 'selectFiles': selection},
+      'res': {
+        'name': 'bundle',
+        'size': size,
+        'files': [
+          {'name': 'a.txt', 'size': 10},
+          {'name': 'b.txt', 'size': 20},
+          {'name': 'c.txt', 'path': 'nested', 'size': 30},
+        ],
+      },
+    },
+    'progress': {'used': 0, 'speed': 0, 'downloaded': 10, 'uploadSpeed': 0, 'uploaded': 0},
+  });
+
+  test('selected files retain original indexes for runtime progress', () {
+    final record = TaskRecord.fromApi(buildTask([2, 0], 40));
+    expect(record.files.map((file) => file.name), ['a.txt', 'c.txt']);
+    expect(record.files.map((file) => file.resourceIndex), [0, 2]);
+    expect(record.files.last.path, 'nested');
+    expect(record.totalBytes, 40);
+    expect(record.progress, 0.25);
+  });
+
+  test('empty selection preserves default all files', () {
+    final record = TaskRecord.fromApi(buildTask([], 60));
+    expect(record.files.length, 3);
+    expect(record.totalBytes, 60);
+  });
+}