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

frontend/app/inventory/ProductForm.tsx

@@ -1,29 +1,40 @@
 'use client';
 
-import { useState, useTransition } from 'react';
-import { createProduct } from './actions';
+import { useState } from 'react';
+import { useRouter } from 'next/navigation';
 
 export default function ProductForm() {
-  const [isPending, startTransition] = useTransition();
+  const [isPending, setIsPending] = useState(false);
   const [error, setError] = useState<string | null>(null);
+  const router = useRouter();
 
   return (
     <form
-      onSubmit={(e) => {
+      onSubmit={async (e) => {
         e.preventDefault();
         setError(null);
 
         const form = e.currentTarget;
-        const formData = new FormData(form);
+        const name = String((new FormData(form)).get('name') || '').trim();
 
-        startTransition(async () => {
-          try {
-            await createProduct(formData);
-            form.reset();
-          } catch (err) {
-            setError(err instanceof Error ? err.message : 'Okänt fel');
+        setIsPending(true);
+        try {
+          const res = await fetch('/api/admin/create-product', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ name }),
+          });
+          if (!res.ok) {
+            const data = await res.json().catch(() => ({}));
+            throw new Error(data?.error || 'Kunde inte skapa produkt');
           }
-        });
+          form.reset();
+          router.refresh();
+        } catch (err) {
+          setError(err instanceof Error ? err.message : 'Okänt fel');
+        } finally {
+          setIsPending(false);
+        }
       }}
       style={{
         display: 'grid',