PR #161 round 2: ReadRegular bypassing readOpened (non-blocking open, no handle check) stayed green, because the search FIFO race used FIFOs with no writer, which read EOF at once. The swapper now opens each FIFO O_RDWR and keeps every writer open until it exits, as any local process could, so a reader that skips the handle check parks forever; the bypass flip is red. The swapper is stopped and awaited in a t.Cleanup before t.TempDir removal (hyperguild#162). Refs #157 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>