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/routes/admin/invoices.ts

@@ -127,13 +127,15 @@ export default async function invoicesRoutes(
 
       const invoice = await createInvoice(body);
 
+      // A draft has no number yet — show "koncept" instead of "null".
+      const isDraft = invoice.status === "draft";
       await logAudit({
         request,
         authData: request.authData,
         action: "create",
         entityType: "invoice",
         entityId: invoice.id,
-        description: `Vytvořena faktura ${invoice.invoice_number}`,
+        description: `Vytvořena faktura ${invoice.invoice_number ?? "koncept"}`,
       });
       // Return both invoice_id and id for frontend compatibility
       return success(
@@ -144,7 +146,9 @@ export default async function invoicesRoutes(
           invoice_number: invoice.invoice_number,
         },
         201,
-        "Faktura byla vystavena",
+        isDraft
+          ? "Faktura byla uložena jako koncept"
+          : "Faktura byla vystavena",
       );
     },
   );