The miroir marathon froze 8+ hours when an iteration ran `miroir-proxy --version`
and the binary never exited, holding the loop's stdout pipe open; 42 leaked
acceptance-test processes accumulated over days under bare `cargo test` (no timeout).
- Add .config/nextest.toml with slow-timeout + terminate-after (hung tests are
killed, not left to wedge the runner)
- instruction.md: replace bare `cargo test` gate with `cargo nextest run`; add
"Test & process hygiene" section requiring nextest for all runs, hard `timeout`
wrappers on ad-hoc binary invocations, deterministic test cleanup, and an orphan
check before iteration exit
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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