feat(api): implement new API routes for bulk category updates, inventory consumption, and product management with authentication

frontend/app/inventory/InventoryForm.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { useState } from 'react';
-import { createInventoryItem } from './actions';
+import { useRouter } from 'next/navigation';
 import type { Product } from '../../features/inventory/types';
 import { UNIT_OPTIONS } from '../../lib/units';
 
@@ -13,6 +13,7 @@ export default function InventoryForm({ products }: Props) {
   const [isPending, setIsPending] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const [isOpen, setIsOpen] = useState(false);
+  const router = useRouter();
 
   const LOCATION_OPTIONS = [
     { value: '', label: 'Välj plats' },
@@ -82,8 +83,32 @@ export default function InventoryForm({ products }: Props) {
         formData.set('quantity', String(quantity));
         formData.set('unit', parsedUnit);
         try {
-          await createInventoryItem(formData);
+          const payload: Record<string, unknown> = {
+            productId: Number(formData.get('productId')),
+            quantity,
+            unit: parsedUnit,
+          };
+          const location = String(formData.get('location') || '').trim();
+          if (location) payload.location = location;
+          payload.opened = formData.get('opened') === 'on';
+          const brand = String(formData.get('brand') || '').trim();
+          if (brand) payload.brand = brand;
+          const suitableFor = String(formData.get('suitableFor') || '').trim();
+          if (suitableFor) payload.suitableFor = suitableFor;
+          const bestBeforeDate = String(formData.get('bestBeforeDate') || '').trim();
+          if (bestBeforeDate) payload.bestBeforeDate = bestBeforeDate;
+
+          const res = await fetch('/api/admin/inventory-item', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify(payload),
+          });
+          if (!res.ok) {
+            const data = await res.json().catch(() => ({}));
+            throw new Error(data?.error || 'Kunde inte spara');
+          }
           form.reset();
+          router.refresh();
         } catch (err) {
           setError(err instanceof Error ? err.message : 'Okänt fel');
         } finally {