fix(database): swallow legacy documents lookup failures

lib/database/app_database.dart

@@ -663,13 +663,18 @@ Future<void> migrateLegacyDesktopDatabase({
   Future<void> Function(File source, String targetPath)? renameOverride,
 }) async {
   final File oldFile;
-  if (sourceOverride != null) {
-    oldFile = sourceOverride;
-  } else {
-    final oldFolder = await getApplicationDocumentsDirectory();
-    oldFile = File(p.join(oldFolder.path, 'plezy_downloads.db'));
+  try {
+    if (sourceOverride != null) {
+      oldFile = sourceOverride;
+    } else {
+      final oldFolder = await getApplicationDocumentsDirectory();
+      oldFile = File(p.join(oldFolder.path, 'plezy_downloads.db'));
+    }
+    if (!await oldFile.exists()) return;
+  } catch (e, st) {
+    appLogger.w('Legacy DB migration skipped before source lookup completed', error: e, stackTrace: st);
+    return;
   }
-  if (!await oldFile.exists()) return;
 
   try {
     if (renameOverride != null) {

test/database/app_database_test.dart

@@ -4,9 +4,11 @@ import 'package:plezy/media/ids.dart';
 import 'package:drift/drift.dart' hide isNull, isNotNull;
 import 'package:drift/native.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
 import 'package:plezy/database/app_database.dart';
 import 'package:plezy/database/download_operations.dart';
 import 'package:plezy/models/download_models.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
 
 void main() {
   final suite = _AppDatabaseTestSuite();
@@ -234,6 +236,20 @@ class _AppDatabaseTestSuite {
         expect(await source.readAsBytes(), [0xAA, 0xBB]);
         expect(await target.exists(), isFalse);
       });
+
+      test('documents directory lookup failure is a silent no-op', () async {
+        final previousPathProvider = PathProviderPlatform.instance;
+        final target = File('${tempDir.path}/AppData/plezy_downloads.db');
+        PathProviderPlatform.instance = _ThrowingDocumentsPathProvider();
+
+        try {
+          await expectLater(migrateLegacyDesktopDatabase(target: target), completes);
+        } finally {
+          PathProviderPlatform.instance = previousPathProvider;
+        }
+
+        expect(await target.exists(), isFalse);
+      });
     });
   }
 
@@ -1029,3 +1045,8 @@ class _AppDatabaseTestSuite {
     });
   }
 }
+
+class _ThrowingDocumentsPathProvider extends PathProviderPlatform with MockPlatformInterfaceMixin {
+  @override
+  Future<String?> getApplicationDocumentsPath() async => throw Exception('documents unavailable');
+}