fix: skip custom domain store detection for platform domains

StoreContextMiddleware was treating platform domains (e.g. rewardflow.lu)
as custom store domains, causing store lookup to fail before reaching
path-based detection (/storefront/FASHIONHUB/...). Now skips custom
domain detection when the host matches the platform's own domain.

Also fixes menu tests to use loyalty-program instead of loyalty-overview,
and adds LOYALTY_DEFAULT_LOGO_URL and LOYALTY_GOOGLE_WALLET_ORIGINS to
Hetzner deployment docs.

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

app/modules/core/tests/integration/test_merchant_menu_routes.py

@@ -278,7 +278,7 @@ class TestMerchantMenuModuleGating:
             s for s in data["sections"] if s["id"] == platform_section_id
         )
         item_ids = {i["id"] for i in platform_section["items"]}
-        assert "loyalty-overview" in item_ids
+        assert "loyalty-program" in item_ids
 
     def test_loyalty_hidden_when_module_not_enabled(
         self, client, db, menu_auth, menu_merchant, menu_subscription,
@@ -296,7 +296,7 @@ class TestMerchantMenuModuleGating:
         self, client, db, menu_auth, menu_merchant, menu_subscription,
         menu_loyalty_module, menu_platform,
     ):
-        """Loyalty overview item has the correct URL."""
+        """Loyalty program item has the correct URL."""
         response = client.get(BASE, headers=menu_auth)
         data = response.json()
         platform_section_id = f"platform-{menu_platform.code}"
@@ -304,9 +304,9 @@ class TestMerchantMenuModuleGating:
             s for s in data["sections"] if s["id"] == platform_section_id
         )
         overview = next(
-            i for i in platform_section["items"] if i["id"] == "loyalty-overview"
+            i for i in platform_section["items"] if i["id"] == "loyalty-program"
         )
-        assert overview["url"] == "/merchants/loyalty/overview"
+        assert overview["url"] == "/merchants/loyalty/program"
 
 
 @pytest.mark.integration
@@ -498,7 +498,7 @@ class TestMerchantMenuMultiPlatform:
             s for s in data["sections"] if s["id"] == platform_a_section_id
         )
         item_ids = {i["id"] for i in pa_section["items"]}
-        assert "loyalty-overview" in item_ids
+        assert "loyalty-program" in item_ids
         # Core sections always present
         assert "main" in section_ids
         assert "billing" in section_ids