Phase 16's FIFO writer-close surfaced as POLLHUP rather than a clean POLLIN+EOF, which the server's poll()-based read loop does not treat as shutdown, so the probe left the process alive and the smoke job failed on every platform. Switch to a plain '< /dev/null' immediate EOF — the server exits reliably (~1s) via its normal getline-EOF path, and it is fully portable (POSIX + MSYS2 bash), so no OS gate is needed. Verified end-to-end: bash scripts/smoke-test.sh reaches 'ALL PASSED'.
Martin Vogel
e83bd73c1a