During stdio MCP server startup, _run_stdio (an async method) called the
synchronous check_package_for_malware() inline. That makes a blocking
urllib HTTPS POST to api.osv.dev whose own timeout doesn't reliably cover a
stalled SSL handshake, so an intermittent network issue froze the entire
asyncio event loop for up to ~120s — blowing past the TUI/gateway's 15s
startup budget and showing "gateway startup timeout".
Run the check via asyncio.to_thread (off the loop) AND bound it with
asyncio.wait_for(timeout=_OSV_MALWARE_CHECK_TIMEOUT_S=12s). The malware check
is fail-open, so on timeout we log and proceed rather than blocking startup.
Salvaged from #29190 by @qdaszx (re-applied on current main — the call site
moved since the PR was opened), combining the to_thread approach also proposed
in #29192 by @ygd58. Two load-bearing tests: event-loop-not-blocked-during-
check and timeout-fails-open — both mutation-verified to fail against the old
inline blocking call.
Closes#29184.
Co-authored-by: ygd58 <buraysandro9@gmail.com>