feat: price home delivery with Jadlog

FREIGHT_ADAPTER=jadlog prices "Receber em casa" through Jadlog's Simulador
de Frete from the order's billed metres and value, adding production days
to Jadlog's delivery time. The package weight is a base plus a weight per
metre from the client, with no default: the adapter refuses to start
without it and without the credentials. The cart re-quotes when the package
changes, and approval quotes again from the server-priced items. The
production stack takes the Jadlog settings, so the read-only probe runs
from the worker's console.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/core/models.py

@@ -41,9 +41,15 @@ class Customer(StrictModel):
         return value.strip()
 
 class Freight(StrictModel):
-    service: Literal['pickup','mock-standard'] = 'pickup'
+    service: Literal['pickup','mock-standard','jadlog'] = 'pickup'
     postal_code: str = Field(default='', max_length=8)
 
+class FreightEstimate(Freight):
+    """The cart's estimate. The charged freight is quoted again by the server
+    from the approved items, never from these numbers."""
+    metres: Decimal | None = Field(default=None, gt=0, le=12000)
+    declared_cents: int = Field(default=0, ge=0, le=100_000_000, strict=True)
+
 UF = Literal['AC','AL','AP','AM','BA','CE','DF','ES','GO','MA','MT','MS','MG','PA','PB',
              'PR','PE','PI','RJ','RN','RS','RO','RR','SC','SP','SE','TO']