feat(meal-plan): add servings field to MealPlanEntry and update related functionality

feat(products): implement bulk update for product categories

feat(recipes): add servings input to WriteRecipePage and update MealPlanClient for servings management

refactor(types): enhance Product and Category types with additional properties

frontend/features/inventory/types.ts

@@ -21,6 +21,13 @@ export type Nutrition = {
   fiber: number | null;
 };
 
+export type Category = {
+  id: number;
+  name: string;
+  parentId: number | null;
+  parent: Category | null;
+};
+
 export type Product = {
   id: number;
   name: string;
@@ -35,6 +42,8 @@ export type Product = {
   updatedAt: string;
   tags?: ProductTag[];
   nutrition?: Nutrition | null;
+  categoryId?: number | null;
+  categoryRef?: Category | null;
 };
 
 export type InventoryItem = {