fix(bookkeeping): editable verifikationstext on andringsverifikation (#1035)

The correction header was always built server-side as
"Rattelse: <original description>". When the original entry was labelled
after the wrong account, the correction kept echoing that stale label even
after the user switched to the correct account (follow-up to the
line-description fix in #1029).

- CorrectJournalEntrySchema gains an optional trimmed description
- correctEntry() accepts options.description; blank or absent falls back
  to the canonical "Rattelse: <original>" auto text
- both correct routes (dashboard + v1, which share the schema) thread the
  description through
- CorrectionEntryDialog surfaces an editable verifikationstext field,
  pre-filled with the auto text; an untouched or cleared prefill is NOT
  sent, so the server-side fallback stays the source of truth (same
  only-overwrite-auto-filled principle as #1029)

Forward-only: already-posted corrections are immutable per BFL.

Fixes #1031

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

components/bookkeeping/correction-entry-description.ts

@@ -0,0 +1,34 @@
+/**
+ * Entry-level verifikationstext handling for the correction dialog.
+ *
+ * The correction header defaults server-side to "Rättelse: <original>"
+ * (lib/core/bookkeeping/storno-service.ts). If the original entry was
+ * labelled after the wrong account (e.g. "Lån från närstående personer,
+ * långfristig del"), that header keeps echoing the wrong label even after
+ * the account itself is corrected (issue #1031). The dialog therefore
+ * pre-fills an editable field with the same auto text and only sends a
+ * description when the user actually changed it: an untouched auto prefill
+ * is omitted from the request so the server-side fallback stays the single
+ * source of truth for the default format. Same only-overwrite-auto-filled
+ * principle as the line-description guard from #1029.
+ */
+
+/** The auto text the server would generate for the correction header. */
+export function autoCorrectionDescription(originalDescription: string): string {
+  return `Rättelse: ${originalDescription}`
+}
+
+/**
+ * Decide what to send as the correction's description.
+ * Returns undefined when the field is blank or still equals the auto prefill:
+ * in both cases the server-side fallback should apply.
+ */
+export function correctionDescriptionForSubmit(
+  currentDescription: string,
+  originalDescription: string,
+): string | undefined {
+  const trimmed = currentDescription.trim()
+  if (!trimmed) return undefined
+  if (trimmed === autoCorrectionDescription(originalDescription).trim()) return undefined
+  return trimmed
+}