Conflict in lib/tcl/test.sh: architecture had bumped `timeout 2400 → 7200`,
this branch had restored it to `timeout 300` based on the Phase 1
quiet-machine measurement (376/376 in 57.8s wall, 16.3s user). Resolved by
keeping `timeout 300` — the 7200s bump was preemptive against contention,
not against an actual substrate regression. Phase 1 confirms the original
180s deadline is comfortable; 300s gives 5× headroom for moderate noise.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>