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>