fix(ios): scan app documents without the Files folder picker

lib/screens/settings/library_settings_page.dart

@@ -17,6 +17,7 @@ import 'package:spotiflac_android/widgets/duplicate_review_sheet.dart';
 import 'package:spotiflac_android/widgets/app_bottom_sheet.dart';
 import 'package:spotiflac_android/widgets/settings_group.dart';
 import 'package:spotiflac_android/widgets/app_sliver_header.dart';
+import 'package:spotiflac_android/widgets/ios_library_folder_sheet.dart';
 
 class LibrarySettingsPage extends ConsumerStatefulWidget {
   const LibrarySettingsPage({super.key});
@@ -137,15 +138,16 @@ class _LibrarySettingsPageState extends ConsumerState<LibrarySettingsPage> {
         }
       }
     } else {
-      // Legacy: request permission and use file picker for older Android / iOS
+      // Older Android needs storage permission; iOS chooses internal or Files.
       if (!_hasStoragePermission) {
         final granted = await _requestStoragePermission();
         if (!granted) return;
       }
       if (Platform.isIOS) {
+        if (!mounted) return;
         IosPickedDirectory? picked;
         try {
-          picked = await PlatformBridge.pickIosDirectory();
+          picked = await showIosLibraryFolderSheet(context);
         } catch (e) {
           if (mounted) {
             ScaffoldMessenger.of(context).showSnackBar(
@@ -160,17 +162,16 @@ class _LibrarySettingsPageState extends ConsumerState<LibrarySettingsPage> {
           }
           return;
         }
-        if (picked != null) {
-          final source = await ref
-              .read(localLibraryProvider.notifier)
-              .addSource(
-                path: picked.path,
-                displayName: picked.path,
-                bookmark: picked.bookmark,
-              );
-          await ref
-              .read(localLibraryProvider.notifier)
-              .startSourceScan(source.id);
+        if (picked != null && mounted) {
+          final library = ref.read(localLibraryProvider.notifier);
+          final source = await library.addSource(
+            path: picked.path,
+            displayName: picked.bookmark.isEmpty
+                ? context.l10n.setupAppDocumentsFolder
+                : picked.path,
+            bookmark: picked.bookmark,
+          );
+          await library.startSourceScan(source.id);
         }
         return;
       }

lib/widgets/ios_library_folder_sheet.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:spotiflac_android/l10n/l10n.dart';
+import 'package:spotiflac_android/services/platform_bridge.dart';
+import 'package:spotiflac_android/widgets/app_bottom_sheet.dart';
+
+enum _LibraryFolderLocation { documents, files }
+
+/// App-owned music does not need a grant from the system Files picker.
+Future<IosPickedDirectory?> showIosLibraryFolderSheet(
+  BuildContext context,
+) async {
+  final location = await showAppModalBottomSheet<_LibraryFolderLocation>(
+    context: context,
+    useRootNavigator: true,
+    builder: (context) => AppBottomSheet(
+      title: context.l10n.libraryAddFolder,
+      child: SingleChildScrollView(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            AppSheetOption(
+              leading: const Icon(Icons.folder_special_outlined),
+              title: Text(context.l10n.setupAppDocumentsFolder),
+              subtitle: Text(context.l10n.setupAppDocumentsFolderSubtitle),
+              onTap: () =>
+                  Navigator.pop(context, _LibraryFolderLocation.documents),
+            ),
+            AppSheetOption(
+              leading: const Icon(Icons.folder_open_outlined),
+              title: Text(context.l10n.setupChooseFromFiles),
+              subtitle: Text(context.l10n.setupChooseFromFilesSubtitle),
+              onTap: () => Navigator.pop(context, _LibraryFolderLocation.files),
+            ),
+            const SizedBox(height: 8),
+          ],
+        ),
+      ),
+    ),
+  );
+  if (location == null || !context.mounted) return null;
+  if (location == _LibraryFolderLocation.files) {
+    // Keep the native picker and its bookmark for folders outside our sandbox.
+    return PlatformBridge.pickIosDirectory();
+  }
+
+  // Scan Documents recursively, including the SpotiFLAC subfolder created by
+  // setup and music the user copied into the app through Files. No bookmark is
+  // needed: app-owned paths can be rebased when iOS relocates the container.
+  final documents = await getApplicationDocumentsDirectory();
+  return IosPickedDirectory(path: documents.path, bookmark: '');
+}