Advertisers
List GAM advertisers
GET /esa/{esaId}/gam/advertisers — cached advertiser recordsEnsure GAM advertiser
POST /esa/{esaId}/gam/advertisers/ensure — create or find by nameSet default advertiser
PUT /esa/{esaId}/gam/default-advertiser — the catch-all advertiserBuyer mappings
List buyer mappings
GET /esa/{esaId}/buyer-advertiser-mappings — per-buyer overrides