feat(db): add database repositories

Upserts keyed on hiboutikId and deletion of the rows that no longer exist in Hiboutik.

src/database/product.database.repository.ts

@@ -0,0 +1,44 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../../prisma/prisma.service';
+import { Product } from '../../prisma/generated/client';
+import { ProductCreateInput } from '../../prisma/generated/models/Product';
+
+/** Database access to products. Rows are matched with Hiboutik by `hiboutikId`. */
+@Injectable()
+export class ProductDatabaseRepository {
+  constructor(private readonly prisma: PrismaService) {}
+
+  async getAll(): Promise<Product[]> {
+    return this.prisma.product.findMany({
+      orderBy: { hiboutikId: 'asc' },
+    });
+  }
+
+  /** Creates or updates the product with the same `hiboutikId`. On update, the relations missing from the input are unlinked. */
+  async upsert(product: ProductCreateInput): Promise<Product> {
+    return this.prisma.product.upsert({
+      where: { hiboutikId: product.hiboutikId },
+      create: product,
+      update: {
+        ...product,
+        // an undefined relation is ignored by Prisma on update: explicitly unlink relations removed in Hiboutik
+        brand: product.brand ?? { disconnect: true },
+        category: product.category ?? { disconnect: true },
+        supplier: product.supplier ?? { disconnect: true },
+      },
+    });
+  }
+
+  /**
+   * Deletes products (and their versions, by cascade).
+   * Order lines keep their own snapshot of the product, their link is set to null.
+   */
+  async deleteAll(productIds: string[]): Promise<number> {
+    if (productIds.length === 0) return 0;
+
+    const result = await this.prisma.product.deleteMany({
+      where: { id: { in: productIds } },
+    });
+    return result.count;
+  }
+}