Fix: Gør e-conomic layout konfigurerbar (layout 21 er historisk)

BUG FIX:
- Hardcoded layout 21 fejler med 'Layout 21 is historic'
- Tilføjet TIMETRACKING_ECONOMIC_LAYOUT setting (default: 19)
- Layout 19 er standard dansk faktura layout
- Kan nu ændres via .env uden kode-ændringer

ERROR: e-conomic API error - layout: Layout '21' is historic
LØSNING: Brug layout 19 eller andet aktivt layout nummer

app/core/config.py

@@ -87,6 +87,7 @@ class Settings(BaseSettings):
     TIMETRACKING_ECONOMIC_READ_ONLY: bool = True
     TIMETRACKING_ECONOMIC_DRY_RUN: bool = True
     TIMETRACKING_EXPORT_TYPE: str = "draft"  # "draft" or "booked"
+    TIMETRACKING_ECONOMIC_LAYOUT: int = 19  # e-conomic invoice layout number (default: 19 = Danish standard)
     
     # Simply-CRM (Old vTiger On-Premise)
     OLD_VTIGER_URL: str = ""

app/timetracking/backend/economic_export.py

@@ -272,7 +272,7 @@ class EconomicExportService:
                     "paymentTermsNumber": 1  # Default payment terms
                 },
                 "layout": {
-                    "layoutNumber": 21  # DK. std. m. bankoplys. 1.8
+                    "layoutNumber": settings.TIMETRACKING_ECONOMIC_LAYOUT
                 },
                 "notes": {
                     "heading": f"Tidsregistrering - {order['order_number']}"