feat: per-ingredient category selection for shopping list transfer (closes #33)

When adding ingredients in the meal editor, each ingredient now has a
category dropdown. Categories are stored on the ingredient and applied
automatically when transferring to the shopping list, so items appear
pre-grouped by category without manual re-sorting.

public/locales/sv.json

@@ -226,6 +226,8 @@
     "addIngredient": "Tillsätt ingrediens",
     "ingredientNamePlaceholder": "Ingrediens",
     "ingredientQtyPlaceholder": "Kvantitet",
+    "ingredientCategoryLabel": "Kategori",
+    "ingredientCategoryDefault": "Övrigt",
     "removeIngredient": "Ta bort ingrediensen",
     "transferLabel": "Överför ingredienserna till inköpslistan",
     "transferNow": "Överför nu",
@@ -596,4 +598,4 @@
     "unitMonth": "månad",
     "unitMonths": "månader"
   }
-}
+}