Move invoice PDF template from app/templates/invoices/ to app/modules/orders/templates/invoices/ where InvoicePDFService expects it. Expand invoice PDF tests to validate template path and existence. Add unit tests for get_merchant_metrics() in tenancy, billing, and customer metrics providers. Add unit tests for StatsAggregatorService merchant methods. Add integration tests for the merchant dashboard stats endpoint. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>