Fix API Error before M5

apps/admin/src/features/products/product-form.tsx

@@ -146,8 +146,17 @@ export function ProductForm({
       translations: filled,
       genderTargets: genders,
       sportTypes: sports,
-      ...(skuPrefix.trim() ? { skuPrefix: skuPrefix.trim() } : {}),
-      basePriceAmount: Number.parseInt(basePrice, 10) || 0,
+      // SKU prefix and base price are create-only fields — the inputs are not
+      // even rendered when editing. Sending them anyway would post
+      // `basePriceAmount: 0`, and the API cannot distinguish "the operator
+      // wants zero" from "the form always sends this", so every variant added
+      // by a later edit would be created free.
+      ...(product
+        ? {}
+        : {
+            ...(skuPrefix.trim() ? { skuPrefix: skuPrefix.trim() } : {}),
+            basePriceAmount: Number.parseInt(basePrice, 10) || 0,
+          }),
       options: options.map((option, index) => ({
         key: option.key,
         position: index,