fix(loyalty): read Google Wallet config from core settings instead of module config

Module config only reads from os.environ (not .env), so wallet settings
were always None. Core Settings already loads these via env_file=".env".
Also adds comprehensive wallet creation tests with mocked Google API.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/loyalty/services/card_service.py

@@ -655,7 +655,10 @@ class CardService:
         query = (
             db.query(LoyaltyTransaction)
             .join(LoyaltyCard, LoyaltyTransaction.card_id == LoyaltyCard.id)
-            .options(joinedload(LoyaltyTransaction.store))
+            .options(
+                joinedload(LoyaltyTransaction.store),
+                joinedload(LoyaltyTransaction.card).joinedload(LoyaltyCard.customer),
+            )
             .filter(LoyaltyCard.merchant_id == merchant_id)
         )
         if store_id:

app/modules/loyalty/services/google_wallet_service.py

@@ -14,7 +14,7 @@ from typing import Any
 
 from sqlalchemy.orm import Session
 
-from app.modules.loyalty.config import config
+from app.core.config import settings
 from app.modules.loyalty.exceptions import (
     GoogleWalletNotConfiguredException,
     WalletIntegrationException,
@@ -35,14 +35,14 @@ class GoogleWalletService:
     @property
     def is_configured(self) -> bool:
         """Check if Google Wallet is configured."""
-        return bool(config.google_issuer_id and config.google_service_account_json)
+        return bool(settings.loyalty_google_issuer_id and settings.loyalty_google_service_account_json)
 
     def _get_credentials(self):
         """Get Google service account credentials."""
         if self._credentials:
             return self._credentials
 
-        if not config.google_service_account_json:
+        if not settings.loyalty_google_service_account_json:
             raise GoogleWalletNotConfiguredException()
 
         try:
@@ -51,7 +51,7 @@ class GoogleWalletService:
             scopes = ["https://www.googleapis.com/auth/wallet_object.issuer"]
 
             self._credentials = service_account.Credentials.from_service_account_file(
-                config.google_service_account_json,
+                settings.loyalty_google_service_account_json,
                 scopes=scopes,
             )
             return self._credentials
@@ -92,7 +92,7 @@ class GoogleWalletService:
         if not self.is_configured:
             raise GoogleWalletNotConfiguredException()
 
-        issuer_id = config.google_issuer_id
+        issuer_id = settings.loyalty_google_issuer_id
         class_id = f"{issuer_id}.loyalty_program_{program.id}"
 
         class_data = {
@@ -203,7 +203,7 @@ class GoogleWalletService:
             # Create class first
             self.create_class(db, program)
 
-        issuer_id = config.google_issuer_id
+        issuer_id = settings.loyalty_google_issuer_id
         object_id = f"{issuer_id}.loyalty_card_{card.id}"
 
         object_data = self._build_object_data(card, object_id)