fix(drafts): exclude drafts from VAT/revenue/created aggregations + koncept audit labels

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/services/invoices.service.ts

@@ -268,6 +268,9 @@ export async function getInvoiceStats(queryMonth?: number, queryYear?: number) {
   const [monthInvoices, awaitingInvoices, overdueInvoices] = await Promise.all([
     prisma.invoices.findMany({
       where: {
+        // Drafts are not real financial documents — exclude them so their
+        // VAT/amounts never inflate the monthly stats (vat_month etc.).
+        status: { not: "draft" },
         issue_date: { gte: monthStart, lte: monthEnd },
       },
       include: { invoice_items: true },