The reconnect-preempt (b53710d, preempt_same_identity) reads the process-global admission table
and signals same-identity live sessions. The three in-process-host tests each bind a fixed loopback
port and share that ONE table, so running them concurrently let one test's connection preempt +
close another's live session — an intermittent `next_au: Closed` in c_abi_connection_roundtrip
(surfaced under full-workspace load; a lucky pass hid it at b53710d). Serialize them on a
poison-tolerant lock. Test-isolation only — in production a host is one process with unique client
certs, so same-identity preempt is correct. Full workspace `cargo test` now green (18 suites, 3× clean).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
334f36ce25