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>

middleware/store_context.py

@@ -59,8 +59,17 @@ class StoreContextManager:
         # Check if this is a custom domain (not platform.com and not localhost)
         platform_domain = getattr(settings, "platform_domain", "platform.com")
 
+        # Skip custom domain detection if host is already a platform domain
+        # (e.g. rewardflow.lu is the loyalty platform, not a store)
+        platform = getattr(request.state, "platform", None)
+        is_platform_domain = (
+            platform and getattr(platform, "domain", None)
+            and host == platform.domain
+        )
+
         is_custom_domain = (
             host
+            and not is_platform_domain
             and not host.endswith(f".{platform_domain}")
             and host != platform_domain
             and host