fix: enrich ingredient names in shopping list API

Same root cause as meal detail: recipe JSONB stores ingredient_id but
not name. Shopping list now looks up names from the Ingredient table
before aggregating quantities, so items show "3 cups onion" instead
of "Unknown".

backend/app/api/shopping_list.py

@@ -71,14 +71,23 @@ def get_shopping_list(db: Session = Depends(get_db)):
 
     aggregated = defaultdict(lambda: {"quantity": 0.0, "unit": None, "name": ""})
 
+    # Build ingredient name lookup from IDs
+    ingredient_names = {}
+    if all_ingredient_ids:
+        ingredient_names = {str(i.id): i.name for i in ingredients}
+
     for plan_item in current_plan.items:
         recipe = db.query(Recipe).filter(Recipe.id == plan_item.recipe_id).first()
         if recipe and recipe.ingredients:
             for ing in recipe.ingredients:
-                name = ing.get('name', 'Unknown')
+                ing_id = ing.get('ingredient_id')
+                name = ing.get('name')
+                if not name and ing_id:
+                    name = ingredient_names.get(str(ing_id))
+                if not name:
+                    name = 'Unknown'
                 quantity = ing.get('quantity', 1.0) or 1.0
                 unit = ing.get('unit')
-                ing_id = ing.get('ingredient_id')
 
                 key = name.lower()
                 aggregated[key]["quantity"] += quantity