Bug/skv konto numbers (#498)

* feat(skattekonto): add overdue transactions handling and split logic

* feat: enhance transaction handling and loading states

- Update BalanceHero component to display last synced date and additional information about Skatteverket updates.
- Refactor BookDirectlyDialog to simplify transaction linking logic and improve UI for transaction selection.
- Revamp InvoiceInboxWorkspace layout for better responsiveness and user experience, including improved skeleton loading states.
- Introduce new loading states for ExtensionWorkspace to match the live layout and improve user feedback during data fetching.
- Implement exchange rate fetching in QuickReviewDialog, ensuring transactions are always processed in SEK with error handling for rate fetching.
- Add structured error handling for unavailable exchange rates in the transaction API.

* feat(skattekonto): add 'Skattekonto – saldo & transaktioner' scope and update authorization checks

* feat: implement reverse charge handling in supplier invoice calculations and UI

lib/errors/structured-errors.ts

@@ -285,6 +285,13 @@ const TRANSACTIONS: Record<string, StructuredErrorEntry> = {
     message_sv: 'Transaktionen har ingen kopplad verifikation att stornera.',
     message_en: 'Transaction has no linked journal entry to reverse.',
   },
+  TX_EXCHANGE_RATE_UNAVAILABLE: {
+    httpStatus: 502,
+    message_sv:
+      'Kunde inte hämta växelkursen från Riksbanken. Försök igen om en stund — verifikationen måste bokföras i SEK.',
+    message_en:
+      'Could not fetch the exchange rate from Riksbanken. The verifikation must be posted in SEK.',
+  },
 }
 
 const MATCH_INVOICE: Record<string, StructuredErrorEntry> = {