feat(invoices): implement öresavrundning logic and next invoice numbe… (#429)

* feat(invoices): implement öresavrundning logic and next invoice number preview

- Added `getDisplayTotal` utility to handle rounding for SEK invoices based on company settings.
- Updated `InvoicesPage` to utilize the new rounding logic when displaying totals.
- Introduced `peek_next_invoice_number` function to allow previewing the next invoice number without consuming the sequence.
- Modified invoice number generation to remove the year prefix and prevent truncation of numbers exceeding three digits.
- Enhanced tests for invoice number generation and rounding functionality to ensure correctness.
- Updated PDF template to reflect new rounding logic for totals and display appropriate values.
- Adjusted company switcher to hide options in sandbox mode.
- Improved error handling and logging in sandbox seeding process.

* fix(skatteverket): remove unused scope labels from SCOPE_LABELS and DEFAULT_SCOPES

components/dashboard/CompanySwitcher.tsx

@@ -9,7 +9,7 @@ import { switchCompany } from '@/lib/company/actions'
 import { Check, ChevronsUpDown, Plus, Loader2 } from 'lucide-react'
 
 export default function CompanySwitcher() {
-  const { company, companies } = useCompany()
+  const { company, companies, isSandbox } = useCompany()
   const [open, setOpen] = useState(false)
   const [isPending, setIsPending] = useState(false)
   const triggerRef = useRef<HTMLButtonElement>(null)
@@ -106,8 +106,9 @@ export default function CompanySwitcher() {
   const hasMultiple = companies.length > 1
 
   // No companies yet — show a direct "Lägg till företag" link instead of
-  // the switcher so the user can still create one.
+  // the switcher so the user can still create one. Hidden in sandbox mode.
   if (!company && companies.length === 0) {
+    if (isSandbox) return null
     return (
       <Link
         href="/select-company"
@@ -187,16 +188,18 @@ export default function CompanySwitcher() {
             </>
           )}
 
-          <div className={cn(companies.length > 0 && 'border-t border-border/40 mt-1 pt-1', 'px-1')}>
-            <Link
-              href="/select-company"
-              onClick={() => setOpen(false)}
-              className="flex items-center gap-2 px-2.5 py-2 text-[13px] text-muted-foreground hover:text-foreground hover:bg-muted/40 rounded-md transition-colors md:whitespace-nowrap"
-            >
-              <Plus className="h-3.5 w-3.5" />
-              Lägg till företag
-            </Link>
-          </div>
+          {!isSandbox && (
+            <div className={cn(companies.length > 0 && 'border-t border-border/40 mt-1 pt-1', 'px-1')}>
+              <Link
+                href="/select-company"
+                onClick={() => setOpen(false)}
+                className="flex items-center gap-2 px-2.5 py-2 text-[13px] text-muted-foreground hover:text-foreground hover:bg-muted/40 rounded-md transition-colors md:whitespace-nowrap"
+              >
+                <Plus className="h-3.5 w-3.5" />
+                Lägg till företag
+              </Link>
+            </div>
+          )}
         </div>,
         document.body
       )}