fix(test): skip legacy profile migration during flutter test runs

Prevent unit tests from copying the developer's com.example profile into
temp dirs, which broke isolated AppSettings expectations.

Author: ZhuchkaTriplesix

lib/core/storage/app_data_root.dart

@@ -142,6 +142,10 @@ abstract final class AppDataRoot {
 
   @visibleForTesting
   static Future<List<Directory>> legacySupportCandidates() async {
+    if (Platform.environment.containsKey('FLUTTER_TEST')) {
+      return mockLegacySupportCandidates ?? const [];
+    }
+
     final home = _env['HOME'] ?? _env['USERPROFILE'];
     if (home == null || home.isEmpty) return const [];
 

test/flutter_test_config.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 
+import 'package:querya_desktop/core/storage/app_data_root.dart';
 import 'package:querya_desktop/core/storage/connection_secrets_store.dart';
 
 import 'memory_secrets_backend.dart';
@@ -8,5 +9,8 @@ import 'memory_secrets_backend.dart';
 Future<void> testExecutable(FutureOr<void> Function() testMain) async {
   ConnectionSecretsStore.backend = testMemorySecrets;
   testMemorySecrets.clear();
+  // Avoid copying the developer's real legacy profile into test temp dirs.
+  AppDataRoot.mockLegacySupportCandidates = const [];
   await testMain();
+  AppDataRoot.resetMocks();
 }