feat(sync): add delivery cost, discount tracking and import settings

Parse delivery.total and discounts[] from GoMag JSON into new
delivery_cost/discount_total fields. Add app_settings table for
configuring transport/discount CODMAT codes. When configured,
transport and discount are appended as extra articles in the
Oracle import JSON. Reorder Total column in dashboard/logs tables
and show transport/discount breakdown in order detail modals.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/services/order_reader.py

@@ -55,6 +55,8 @@ class OrderData:
     billing: OrderBilling = field(default_factory=OrderBilling)
     shipping: Optional[OrderShipping] = None
     total: float = 0.0
+    delivery_cost: float = 0.0
+    discount_total: float = 0.0
     payment_name: str = ""
     delivery_name: str = ""
     source_file: str = ""
@@ -155,6 +157,15 @@ def _parse_order(order_id: str, data: dict, source_file: str) -> OrderData:
     payment = data.get("payment", {}) or {}
     delivery = data.get("delivery", {}) or {}
 
+    # Parse delivery cost
+    delivery_cost = float(delivery.get("total", 0) or 0) if isinstance(delivery, dict) else 0.0
+
+    # Parse discount total (sum of all discount values)
+    discount_total = 0.0
+    for d in data.get("discounts", []):
+        if isinstance(d, dict):
+            discount_total += float(d.get("value", 0) or 0)
+
     return OrderData(
         id=str(data.get("id", order_id)),
         number=str(data.get("number", "")),
@@ -165,6 +176,8 @@ def _parse_order(order_id: str, data: dict, source_file: str) -> OrderData:
         billing=billing,
         shipping=shipping,
         total=float(data.get("total", 0) or 0),
+        delivery_cost=delivery_cost,
+        discount_total=discount_total,
         payment_name=str(payment.get("name", "")) if isinstance(payment, dict) else "",
         delivery_name=str(delivery.get("name", "")) if isinstance(delivery, dict) else "",
         source_file=source_file