Update product naming convention for DLC items

Rename `productName` to `name` in `dlcProducts` schema and map `productName` to `name` in `DlcPage.tsx` for database compatibility.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 1e4433b5-47ab-464c-b663-fea2e53367dd
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/1e4433b5-47ab-464c-b663-fea2e53367dd/62NL8Ye

client/src/pages/DlcPage.tsx

@@ -264,6 +264,7 @@ export default function DlcPage() {
     
     const dlcData: InsertDlcProduct = {
       ...data,
+      name: data.productName, // Copier productName vers name (requis dans la DB)
       expiryDate: dlcDate,
       quantity: 1, // Valeur par défaut
       unit: "unité", // Valeur par défaut