ok for now

lib/services/storage_service.dart

@@ -1,10 +1,26 @@
 /// Thin wrapper around [SharedPreferences] for local key-value persistence.
 library;
 
+import 'dart:convert';
+
 import 'package:shared_preferences/shared_preferences.dart';
 
+import '../models/transaction_meta.dart';
 import '../utils/constants.dart';
 
+/// Persisted annotation store for transactions.
+class TxMetaStoreData {
+  const TxMetaStoreData({
+    this.byId = const {},
+    this.categoryByDescription = const {},
+    this.exactTemplates = const {},
+  });
+
+  final Map<String, TxMeta> byId;
+  final Map<String, TxCategory> categoryByDescription;
+  final Map<String, TxExactTemplate> exactTemplates;
+}
+
 /// Loads and stores user preferences. Call [init] once at startup.
 class StorageService {
   StorageService({this._preferences});
@@ -35,4 +51,123 @@ class StorageService {
   Future<void> setUseRemoteData(bool value) {
     return _prefs.setBool(StorageKeys.useRemoteData, value);
   }
+
+  TxMetaStoreData loadTxMetaStore() {
+    final raw = _prefs.getString(StorageKeys.txMeta);
+    if (raw != null && raw.isNotEmpty) {
+      return _decodeStore(raw);
+    }
+
+    // Migrate flat v1 map → v2 store.
+    final legacy = _prefs.getString(StorageKeys.txMetaLegacy);
+    if (legacy == null || legacy.isEmpty) return const TxMetaStoreData();
+    try {
+      final decoded = jsonDecode(legacy);
+      if (decoded is! Map) return const TxMetaStoreData();
+      final byId = <String, TxMeta>{};
+      final categoryByDescription = <String, TxCategory>{};
+      decoded.forEach((key, value) {
+        if (key is! String || value is! Map) return;
+        final meta = TxMeta.fromJson(Map<String, dynamic>.from(value));
+        byId[key] = meta;
+        if (meta.hasCategory) {
+          final desc = _descriptionFromLegacyId(key);
+          if (desc != null) {
+            categoryByDescription[desc] = meta.category;
+          }
+        }
+      });
+      return TxMetaStoreData(
+        byId: byId,
+        categoryByDescription: categoryByDescription,
+      );
+    } catch (_) {
+      return const TxMetaStoreData();
+    }
+  }
+
+  Future<void> saveTxMetaStore(TxMetaStoreData store) {
+    final encoded = {
+      'byId': {
+        for (final e in store.byId.entries) e.key: e.value.toJson(),
+      },
+      'categoryByDescription': {
+        for (final e in store.categoryByDescription.entries)
+          e.key: e.value.name,
+      },
+      'exactTemplates': {
+        for (final e in store.exactTemplates.entries) e.key: e.value.toJson(),
+      },
+    };
+    return _prefs.setString(StorageKeys.txMeta, jsonEncode(encoded));
+  }
+
+  /// Deprecated shim used by older call sites during transition.
+  Map<String, TxMeta> loadTxMeta() => loadTxMetaStore().byId;
+
+  Future<void> saveTxMeta(Map<String, TxMeta> meta) {
+    final current = loadTxMetaStore();
+    return saveTxMetaStore(
+      TxMetaStoreData(
+        byId: meta,
+        categoryByDescription: current.categoryByDescription,
+        exactTemplates: current.exactTemplates,
+      ),
+    );
+  }
+
+  TxMetaStoreData _decodeStore(String raw) {
+    try {
+      final decoded = jsonDecode(raw);
+      if (decoded is! Map) return const TxMetaStoreData();
+      final root = Map<String, dynamic>.from(decoded);
+
+      final byId = <String, TxMeta>{};
+      final byIdRaw = root['byId'];
+      if (byIdRaw is Map) {
+        byIdRaw.forEach((key, value) {
+          if (key is String && value is Map) {
+            byId[key] = TxMeta.fromJson(Map<String, dynamic>.from(value));
+          }
+        });
+      }
+
+      final categoryByDescription = <String, TxCategory>{};
+      final cats = root['categoryByDescription'];
+      if (cats is Map) {
+        cats.forEach((key, value) {
+          if (key is String && value is String) {
+            categoryByDescription[key] = TxCategoryX.fromName(value);
+          }
+        });
+      }
+
+      final exactTemplates = <String, TxExactTemplate>{};
+      final templates = root['exactTemplates'];
+      if (templates is Map) {
+        templates.forEach((key, value) {
+          if (key is String && value is Map) {
+            exactTemplates[key] =
+                TxExactTemplate.fromJson(Map<String, dynamic>.from(value));
+          }
+        });
+      }
+
+      return TxMetaStoreData(
+        byId: byId,
+        categoryByDescription: categoryByDescription,
+        exactTemplates: exactTemplates,
+      );
+    } catch (_) {
+      return const TxMetaStoreData();
+    }
+  }
+
+  /// Legacy id format: `date|currency|amount|description`.
+  String? _descriptionFromLegacyId(String id) {
+    final parts = id.split('|');
+    if (parts.length < 4) return null;
+    final description = parts.sublist(3).join('|');
+    return description.trim().toLowerCase().replaceAll(RegExp(r'\s+'), ' ');
+  }
 }