Finding 8(a): every spawnServeProcess call used stdio ["ignore", ...], which
hands the C# quic-realtime-serve peer an already-closed stdin. Its own
WatchStdinCloseAsync (Program.cs:1261-1269) treats that as EOF and tears the
serve loop down at once, before it can send anything. spawnServeProcess gains
an opt-in `stdin: "pipe"` (default stays "ignore" for every other serve mode,
which never reads stdin), used only by the "CultMesh QUIC realtime" test; its
teardown ends that pipe explicitly before killing the process.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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