fix(bookkeeping): let a rättelseverifikation be stornoed; unblock aged supplier-invoice deletion (#1204)

* fix(bookkeeping): let a rättelseverifikation be stornoed; unblock aged supplier-invoice deletion

A user who corrected a booking (storno + rättelse) and then discovered the
affärshändelse was already booked by another verifikat had no sanctioned way
out: reverseEntry refused source_type 'correction' alongside 'storno', and
correctEntry rightly rejects a zeroing rättelse (BFL 5 kap 5 §). The same
guard also broke uncategorize-after-rättelse, since bank transactions are
relinked to the correction entry.

- reverseEntry now blocks only 'storno' (storno-of-a-storno keeps the chain
  ambiguity problem); a correction entry is a regular live verifikat and can
  be stornoed, with correction_of_id keeping the chain traceable.
- CANNOT_REVERSE_STORNO copy narrowed to stornos + remediation hint.
- Supplier-invoice DELETE now allows unbooked, unpaid invoices in
  registered/approved/overdue: the daily overdue cron flipped unbooked
  invoices past due_date into a state where deletion was blocked forever.
  Orphan-safety checks (registration JE, payments, accrual schedule) are what
  actually protect the books. UI shows the delete button accordingly.
- LinkVoucherPicker showed customer-side copy (kundfordran/1510) in
  supplier-invoice mode; supplier mode now explains the 2440-debit
  requirement, including why a direct-cost verifikat cannot be linked.

Support case 2026-07-26 (marcus@).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(supplier-invoices): review fixes: fail-closed orphan lookups, hide delete when payments loaded

- The payment and accrual-schedule lookups in DELETE now fail closed: a
  lookup error returns 500 instead of reading as "nothing linked" and
  letting the delete proceed unverified.
- The delete button also requires the loaded payment list to be empty,
  matching the server predicate.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs: authorize 'approved' in supplier-invoice delete allow-list (compliance-swarm V2.3)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

messages/en.json

@@ -3457,6 +3457,8 @@
     "empty_title": "No matching journal entries found",
     "empty_description": "No posted entry credits 1510 in this invoice's currency and date window. Post a new payment instead, or correct the prior bookkeeping first.",
     "empty_description_cash": "No posted entry debits a cash/bank account (19xx) in this invoice's currency and date window. Post a new payment instead, or correct the prior bookkeeping first.",
+    "intro_supplier": "Pick an existing posted journal entry that debits accounts payable (2440). No new entry is created: you only link the existing one as the payment.",
+    "empty_description_supplier": "No posted entry debits accounts payable (2440) in this invoice's currency and date window. If the cost was booked straight against e.g. the bank account without 2440, it cannot be linked as a payment here: book the invoice from supplier invoices instead, or record a new payment.",
     "confirmation": "This links voucher {voucher} ({amount}) as the payment for the invoice.",
     "no_new_je_note": "No new bookkeeping is created: the existing journal entry is the payment posting.",
     "cancel": "Cancel",

messages/sv.json

@@ -3457,6 +3457,8 @@
     "empty_title": "Inga matchande verifikationer hittades",
     "empty_description": "Det finns ingen bokförd verifikation som krediterar 1510 i fakturans valuta och period. Bokför istället en ny betalning, eller rätta tidigare bokföring först.",
     "empty_description_cash": "Det finns ingen bokförd verifikation som debiterar ett likvidkonto (19xx) i fakturans valuta och period. Bokför istället en ny betalning, eller rätta tidigare bokföring först.",
+    "intro_supplier": "Välj en befintlig verifikation som debiterar leverantörsskulder (2440). Ingen ny verifikation skapas: du länkar bara den befintliga som betalning.",
+    "empty_description_supplier": "Det finns ingen bokförd verifikation som debiterar leverantörsskulder (2440) i fakturans valuta och period. Om kostnaden bokfördes direkt mot t.ex. bank utan 2440 kan den inte länkas som betalning här: bokför istället fakturan från leverantörsfakturor, eller registrera en ny betalning.",
     "confirmation": "Detta länkar verifikat {voucher} ({amount}) som betalning för fakturan.",
     "no_new_je_note": "Ingen ny bokföring skapas: den befintliga verifikationen utgör betalningsposten.",
     "cancel": "Avbryt",