feat: add support for alternative ingredients; implement JSON storage and parsing logic

flutter/lib/features/recipes/domain/parsed_recipe.dart

@@ -23,6 +23,7 @@ class ParsedIngredient {
   final String unit;
   final String? note;
   final List<IngredientSuggestion> suggestions;
+  final List<String> alternatives;
 
   const ParsedIngredient({
     required this.rawName,
@@ -30,6 +31,7 @@ class ParsedIngredient {
     required this.unit,
     this.note,
     required this.suggestions,
+    this.alternatives = const [],
   });
 
   factory ParsedIngredient.fromJson(Map<String, dynamic> json) {
@@ -42,6 +44,9 @@ class ParsedIngredient {
       suggestions: rawSuggestions
           .map((s) => IngredientSuggestion.fromJson(s as Map<String, dynamic>))
           .toList(),
+      alternatives: (json['alternatives'] as List<dynamic>? ?? [])
+          .map((a) => a as String)
+          .toList(),
     );
   }
 }

flutter/lib/features/recipes/presentation/create_recipe_screen.dart

@@ -149,11 +149,21 @@ class _CreateRecipeScreenState extends ConsumerState<CreateRecipeScreen> {
           _parsed!.ingredients[i].quantity;
       final unit = _unitControllers[i]!.text.trim();
       final note = _noteControllers[i]!.text.trim();
+      final ing = _parsed!.ingredients[i];
+      // Alternativa produkter: alla suggestions vars productId matchar ett alternativ
+      final alternativeProductIds = ing.alternatives.length > 1
+          ? ing.suggestions
+              .where((s) => s.productId != productId)
+              .map((s) => s.productId)
+              .toList()
+          : <int>[];
       ingredients.add({
         'productId': productId,
         'quantity': qty,
         'unit': unit,
         if (note.isNotEmpty) 'note': note,
+        if (alternativeProductIds.isNotEmpty)
+          'alternativeProductIds': alternativeProductIds,
       });
     }
 
@@ -339,7 +349,19 @@ class _CreateRecipeScreenState extends ConsumerState<CreateRecipeScreen> {
           CheckboxListTile(
             value: isIncluded,
             onChanged: (v) => setState(() => _included[index] = v ?? false),
-            title: Text(ing.rawName),
+            title: ing.alternatives.length > 1
+              ? Wrap(
+                spacing: 4,
+                children: ing.alternatives
+                  .map((alt) => Chip(
+                      label: Text(alt),
+                      padding: EdgeInsets.zero,
+                      materialTapTargetSize:
+                        MaterialTapTargetSize.shrinkWrap,
+                    ))
+                  .toList(),
+                )
+              : Text(ing.rawName),
             subtitle: noProductFound
                 ? Text(
                     context.l10n.recipeCreateNoProductFound,