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

backend/src/products/products.controller.ts

@@ -17,7 +17,7 @@ import { ProductsService } from './products.service';
 import { MergeProductsDto } from './dto/merge-products.dto';
 import { UpdateCanonicalNameDto } from './dto/update-canonical-name.dto';
 import { SetTagsDto } from './dto/set-tags.dto';
-import { UpsertNutritionDto } from './dto/upsert-nutrition.dto';
+import { BulkUpdateProductsDto } from './dto/bulk-update-products.dto';
 
 @Controller('products')
 export class ProductsController {
@@ -116,4 +116,10 @@ export class ProductsController {
   resetAll() {
     return this.productsService.resetAll();
   }
+
+  @Post('bulk-update')
+  @HttpCode(200)
+  bulkUpdate(@Body() body: BulkUpdateProductsDto) {
+    return this.productsService.bulkUpdate(body.ids, { categoryId: body.categoryId });
+  }
 }