Edit a dashboard's name or description.

Requires MEMBER role or higher in the project's workspace (the write service decides). A null description clears it.

Args: request (Request): Incoming request (rate-limit plumbing). response (Response): Outgoing response (rate-limit plumbing). auth (AccountStampedAuth): Account-scope user auth (session token or CLI access JWT); its resolved user_id becomes the actor. dashboard_id (str): The dashboard to edit. payload (UpdateDashboardRequest): The project and the fields to change. _live (None): Write-path liveness gate (blocks a revoked JWT session).

Returns: UpdateDashboardResponse: The updated dashboard and the changed fields.

Raises: HTTPException: The write service's 400/403/404/409 verbatim, or a 503 when its response is ambiguous.