The merchant dashboard was showing subscription count as "Total Stores". Add get_merchant_metrics() to MetricsProviderProtocol and implement it in tenancy, billing, and customer providers. Dashboard now fetches real stats from a new /merchants/core/dashboard/stats endpoint and displays 4 cards: active subscriptions, total stores, customers, team members. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>