feat(receipt-import): enhance bread category detection and improve session management

Co-authored-by: Copilot <copilot@github.com>

flutter/lib/features/import/data/receipt_import_session.dart

@@ -1,5 +1,8 @@
 import 'dart:typed_data';
+import 'dart:convert';
+import 'dart:async';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 import '../domain/parsed_receipt_item.dart';
 
 // ── Destination-enum ──────────────────────────────────────────────────────────
@@ -43,6 +46,7 @@ class ItemEdit {
 class ReceiptImportSession {
   final Uint8List? fileBytes;
   final String? fileExtension;
+  final String? fileName;
   final List<ParsedReceiptItem>? items; // null = ej parsad än
   final Map<int, ItemEdit> edits;
   final Map<int, bool> selected;
@@ -50,6 +54,7 @@ class ReceiptImportSession {
   const ReceiptImportSession({
     this.fileBytes,
     this.fileExtension,
+    this.fileName,
     this.items,
     this.edits = const {},
     this.selected = const {},
@@ -58,6 +63,7 @@ class ReceiptImportSession {
   ReceiptImportSession copyWith({
     Uint8List? fileBytes,
     String? fileExtension,
+    String? fileName,
     List<ParsedReceiptItem>? items,
     Map<int, ItemEdit>? edits,
     Map<int, bool>? selected,
@@ -65,42 +71,168 @@ class ReceiptImportSession {
       ReceiptImportSession(
         fileBytes: fileBytes ?? this.fileBytes,
         fileExtension: fileExtension ?? this.fileExtension,
+        fileName: fileName ?? this.fileName,
         items: items ?? this.items,
         edits: edits ?? this.edits,
         selected: selected ?? this.selected,
       );
+
+  Map<String, dynamic> toJson() => {
+    'fileBytes': fileBytes == null ? null : base64Encode(fileBytes!),
+    'fileExtension': fileExtension,
+    'fileName': fileName,
+    'items': items?.map((e) => e.toJson()).toList(),
+    'edits': edits.map((key, value) => MapEntry(key.toString(), {
+      'productId': value.productId,
+      'productName': value.productName,
+      'categoryId': value.categoryId,
+      'categoryPath': value.categoryPath,
+      'categorySource': value.categorySource?.name,
+      'quantity': value.quantity,
+      'unit': value.unit,
+      'packQuantity': value.packQuantity,
+      'packUnit': value.packUnit,
+      'packageCount': value.packageCount,
+      'destination': value.destination.name,
+    })),
+    'selected': selected.map((key, value) => MapEntry(key.toString(), value)),
+  };
+
+  factory ReceiptImportSession.fromJson(Map<String, dynamic> json) {
+    final rawItems = json['items'] as List<dynamic>?;
+    final items = rawItems
+        ?.whereType<Map<String, dynamic>>()
+        .map(ParsedReceiptItem.fromJson)
+        .toList();
+
+    final rawEdits = (json['edits'] as Map<String, dynamic>? ?? {});
+    final edits = <int, ItemEdit>{};
+    for (final entry in rawEdits.entries) {
+      final idx = int.tryParse(entry.key);
+      final value = entry.value;
+      if (idx == null || value is! Map<String, dynamic>) continue;
+      edits[idx] = ItemEdit(
+        productId: (value['productId'] as num?)?.toInt(),
+        productName: value['productName'] as String?,
+        categoryId: (value['categoryId'] as num?)?.toInt(),
+        categoryPath: value['categoryPath'] as String?,
+        categorySource: switch (value['categorySource']) {
+          'ai' => CategorySelectionSource.ai,
+          'manual' => CategorySelectionSource.manual,
+          _ => null,
+        },
+        quantity: (value['quantity'] as num?)?.toDouble(),
+        unit: value['unit'] as String?,
+        packQuantity: (value['packQuantity'] as num?)?.toDouble(),
+        packUnit: value['packUnit'] as String?,
+        packageCount: (value['packageCount'] as num?)?.toDouble(),
+        destination: (value['destination'] as String?) == ImportDestination.pantry.name
+            ? ImportDestination.pantry
+            : ImportDestination.inventory,
+      );
+    }
+
+    final rawSelected = (json['selected'] as Map<String, dynamic>? ?? {});
+    final selected = <int, bool>{};
+    for (final entry in rawSelected.entries) {
+      final idx = int.tryParse(entry.key);
+      if (idx == null) continue;
+      selected[idx] = entry.value == true;
+    }
+
+    Uint8List? fileBytes;
+    final fileBytesRaw = json['fileBytes'];
+    if (fileBytesRaw is String && fileBytesRaw.isNotEmpty) {
+      try {
+        fileBytes = base64Decode(fileBytesRaw);
+      } catch (_) {
+        fileBytes = null;
+      }
+    }
+
+    return ReceiptImportSession(
+      fileBytes: fileBytes,
+      fileExtension: json['fileExtension'] as String?,
+      fileName: json['fileName'] as String?,
+      items: items,
+      edits: edits,
+      selected: selected,
+    );
+  }
 }
 
 // ── Notifier ──────────────────────────────────────────────────────────────────
 
 class ReceiptImportSessionNotifier
     extends Notifier<ReceiptImportSession?> {
+  static const _storageKey = 'receipt_import_session_v1';
+
   @override
   ReceiptImportSession? build() => null;
 
   /// Ny fil vald — återställer items/edits/selected, behåller ingenting gammalt.
-  void setFile(Uint8List bytes, String extension) {
-    state = ReceiptImportSession(fileBytes: bytes, fileExtension: extension);
+  void setFile(Uint8List bytes, String extension, {String? fileName}) {
+    state = ReceiptImportSession(
+      fileBytes: bytes,
+      fileExtension: extension,
+      fileName: fileName,
+    );
+    unawaited(_persist());
   }
 
   void setItems(List<ParsedReceiptItem> items) {
     // Bevara filinformationen när items sätts
     state = (state ?? const ReceiptImportSession()).copyWith(items: items);
+    unawaited(_persist());
   }
 
   void setEdit(int index, ItemEdit edit) {
     if (state == null) return;
     final edits = Map<int, ItemEdit>.from(state!.edits)..[index] = edit;
     state = state!.copyWith(edits: edits);
+    unawaited(_persist());
   }
 
   void setSelected(int index, bool value) {
     if (state == null) return;
     final selected = Map<int, bool>.from(state!.selected)..[index] = value;
     state = state!.copyWith(selected: selected);
+    unawaited(_persist());
   }
 
-  void clear() => state = null;
+  Future<void> restore() async {
+    final prefs = await SharedPreferences.getInstance();
+    final raw = prefs.getString(_storageKey);
+    if (raw == null || raw.isEmpty) return;
+
+    try {
+      final decoded = jsonDecode(raw);
+      if (decoded is Map<String, dynamic>) {
+        state = ReceiptImportSession.fromJson(decoded);
+      }
+    } catch (_) {
+      await prefs.remove(_storageKey);
+    }
+  }
+
+  void clear() {
+    state = null;
+    unawaited(_removePersisted());
+  }
+
+  Future<void> _persist() async {
+    final prefs = await SharedPreferences.getInstance();
+    if (state == null) {
+      await prefs.remove(_storageKey);
+      return;
+    }
+    await prefs.setString(_storageKey, jsonEncode(state!.toJson()));
+  }
+
+  Future<void> _removePersisted() async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.remove(_storageKey);
+  }
 }
 
 final receiptImportSessionProvider =