feat(categories): implement category management with hierarchical structure and update product association

backend/src/products/dto/update-product.dto.ts

@@ -1,4 +1,4 @@
-import { IsNotEmpty, IsOptional, IsString, MaxLength } from 'class-validator';
+import { IsNotEmpty, IsNumber, IsOptional, IsString, MaxLength } from 'class-validator';
 
 export class UpdateProductDto {
   @IsOptional()
@@ -26,4 +26,8 @@ export class UpdateProductDto {
   @IsString()
   @MaxLength(191)
   brand?: string;
+
+  @IsOptional()
+  @IsNumber()
+  categoryId?: number | null;
 }

backend/src/products/products.service.ts

@@ -21,6 +21,7 @@ export class ProductsService {
       include: {
         tags: { include: { tag: true } },
         nutrition: true,
+        categoryRef: { include: { parent: { include: { parent: true } } } },
       },
       orderBy: { name: 'asc' },
     });
@@ -114,6 +115,7 @@ export class ProductsService {
       category?: string | null;
       subcategory?: string | null;
       brand?: string | null;
+      categoryId?: number | null;
     } = {};
 
     if (typeof data.name === 'string') {
@@ -160,6 +162,10 @@ export class ProductsService {
       updateData.brand = data.brand.trim() || null;
     }
 
+    if ('categoryId' in data) {
+      updateData.categoryId = data.categoryId ?? null;
+    }
+
     return this.prisma.product.update({
       where: { id },
       data: updateData,