External partner API (web): /external/v1 endpoints (catalogMaster, catalogSkuMaster, skuMaster, storeMaster + catalogs/catalogSkus/stock lookups), X-Api-Key ApiKeyInterceptor on /external/** (excluded from JWT/CORS/post interceptors), hosted partner docs at /external/v1/docs. Requires migration_external_api_client.sql (r37149) on DB before deploy.