Start a client project

Create one deep client report against the shared Agency project quota. Never falls back to personal credits. Async: 202 on a new dispatch, 200 with reused=true when the clientRunId replays an existing report. clientRunId is scoped to the calling key; reusing one that belongs to a different workspace is 409 CLIENT_RUN_ID_CONFLICT. A response carrying dispatchPending=true means the dispatch outcome is unknown - retry the same clientRunId and arguments after 60 seconds; recovery reuses the original report and credit. 503 TRIGGER_DISPATCH_FAILED is a definite rejection: the credit was restored and that request stays failed on replay, so a new attempt needs a new clientRunId. Creating a report here does not email the client or publish a share link.