Atomically delete all Lives in this workspace

Delete all Lives in the service token’s organization in one account-locked transaction. Current authority is rechecked after lock acquisition; foreign organizations return 404. Returns 200 with the actual deleted count, including zero. No per-Live If-Match is used. Concurrent creation serializes on the account lock; session shutdown follows committed deletion. Idempotency-Key is unsupported. Inspect the collection after an ambiguous response instead of blindly retrying, since a later retry could delete newly created Lives.

Required scopes: live.delete. Scopes intersect current authority; browser cookies never authenticate REST.