feat(arcim-migration): import the Fortnox asset register during migration (#1999)

The Fortnox migration now imports the asset register (GET /3/assets + /3/assets/types) as local register rows via createAsset: category from the type's anskaffningskonto BAS class, useful life from the source's depreciation window (K2 schablon fallback), never any journal entries (values arrived via SIE; the source's depreciated-to date is recorded in notes for review of the first proposal). Sold/scrapped/voided assets are skipped, re-runs dedupe, one bad asset counts as skipped. Gated behind FORTNOX_ASSET_SCOPES_APPROVED=false until the portal registration for integration 39254 carries the Assets scope, so hosted consents are unchanged and the wizard shows an honest skipped row.

Co-authored-by: pgronberg <pgronberg@users.noreply.github.com>

lib/errors/structured-errors.ts

@@ -2241,9 +2241,9 @@ const PROVIDER_MIGRATION: Record<string, StructuredErrorEntry> = {
   PROVIDER_SIE_IMPORT_REQUIRED: {
     httpStatus: 409,
     message_sv:
-      'Bokföringsdata (SIE) måste importeras först. Ladda upp en SIE-fil med kontoplan, ingående balanser och verifikationer innan du hämtar kunder, leverantörer och fakturor från den här leverantören.',
+      'Bokföringsdata (SIE) måste importeras först. Ladda upp en SIE-fil med kontoplan, ingående balanser och verifikationer innan du hämtar kunder, leverantörer, fakturor och anläggningstillgångar från den här leverantören.',
     message_en:
-      'A completed SIE import is required first. Import the SIE file (chart of accounts, opening balances and verifications) before importing customers, suppliers and invoices from this provider.',
+      'A completed SIE import is required first. Import the SIE file (chart of accounts, opening balances and verifications) before importing customers, suppliers, invoices and fixed assets from this provider.',
   },
   PROVIDER_MIGRATE_FAILED: {
     httpStatus: 500,