fix: address user feedback — AI loan categorization, invoice UX, email extension, supplier module

- #43: Improve AI categorization to use account 2350 for loan repayments
  instead of incorrectly suggesting 2440 (supplier payables). Add explicit
  prompt guidance distinguishing loans from supplier debts.
- #45: Change unclear invoice unit "mån" to "månad"
- #46: Enable email extension in extensions.config.json so it appears in
  the marketplace and can be activated by users
- #47: Change "Makulera" to "Ta bort utkast" for draft invoices — reserve
  "Makulera" terminology for proforma invoices only
- #48: Show field-level validation errors when supplier creation fails
  instead of generic "Validation failed" message
- #49: Temporarily hide Leverantörer and Leverantörsfakturor from sidebar
  pending module rework

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/(dashboard)/invoices/[id]/page.tsx

@@ -29,6 +29,7 @@ import {
   Bell,
   AlertTriangle,
   MessageSquare,
+  Trash2,
 } from 'lucide-react'
 import type { Invoice, InvoiceItem, Customer, InvoiceStatus, InvoiceReminder, InvoiceDocumentType } from '@/types'
 
@@ -875,12 +876,12 @@ export default function InvoiceDetailPage({ params }: { params: Promise<{ id: st
                     )}
                     <Button
                       variant="outline"
-                      className="w-full"
+                      className="w-full text-destructive hover:text-destructive"
                       onClick={() => updateStatus('cancelled')}
                       disabled={isUpdating}
                     >
-                      <XCircle className="mr-2 h-4 w-4" />
-                      Makulera
+                      <Trash2 className="mr-2 h-4 w-4" />
+                      Ta bort utkast
                     </Button>
                   </>
                 )}

app/(dashboard)/invoices/new/page.tsx

@@ -49,7 +49,7 @@ const schema = z.object({
 type FormData = z.infer<typeof schema>
 
 const currencies: Currency[] = ['SEK', 'EUR', 'USD', 'GBP', 'NOK', 'DKK']
-const units = ['st', 'tim', 'dag', 'mån', 'km', 'kg']
+const units = ['st', 'tim', 'dag', 'månad', 'km', 'kg']
 
 export default function NewInvoicePage() {
   const router = useRouter()

app/(dashboard)/suppliers/[id]/page.tsx

@@ -68,7 +68,8 @@ export default function SupplierDetailPage() {
     })
     const result = await res.json()
     if (!res.ok) {
-      toast({ title: 'Fel', description: result.error, variant: 'destructive' })
+      const fieldErrors = result.errors?.map((e: { field: string; message: string }) => `${e.field}: ${e.message}`).join(', ')
+      toast({ title: 'Fel', description: fieldErrors || result.error || 'Kunde inte uppdatera leverantör', variant: 'destructive' })
     } else {
       toast({ title: 'Sparat', description: 'Leverantören har uppdaterats' })
       setSupplier({ ...result.data, stats: supplier?.stats })

app/(dashboard)/suppliers/page.tsx

@@ -69,9 +69,10 @@ export default function SuppliersPage() {
     const result = await response.json()
 
     if (!response.ok) {
+      const fieldErrors = result.errors?.map((e: { field: string; message: string }) => `${e.field}: ${e.message}`).join(', ')
       toast({
         title: 'Fel',
-        description: result.error || 'Kunde inte skapa leverantör',
+        description: fieldErrors || result.error || 'Kunde inte skapa leverantör',
         variant: 'destructive',
       })
     } else {