Development record

On the Linux CI race lane, TestStartNeverSignalsAServerThatAlreadyExited failed in 0.03s: dashboard start killed the process group of a server that had already exited. A server that exits at once closes its configuration pipe before start writes to it; on Linux the write fails with EPIPE, and start treated that error as a stuck server and killed its group at once, while a concurrent cmd.Wait could already have reaped it, so the group number could by then name another program's processes. macOS passed only because the write lands in the pipe first.