List Meta and TikTok ad accounts the calling workspace has connected. Use the returned id as account_id on the per-account endpoints (/open/v1/ad-accounts/{account_id}/summary, /open/v1/ad-accounts/{account_id}/ads, /open/v1/ad-accounts/{account_id}/ads/{platform_ad_id}).

Scoped to the workspace bound to your API key. No pagination — workspaces rarely connect more than a handful of accounts.

Returns: code=0 success; code=40001 workspace context missing.