tools/heat-gate.mjs reads the HEAT lines of an app log and passes a hold within 1 degree for 4 hours with the hash
following the slice; its self-test fires on a known hold, a drift, a hash through the rest, a short log, an empty log
and a log without readings, and sits on the one gate beside heat-region.test.mjs. docs/plans/ember-heat.md carries
the words, the loop, the sources, the per-tier table and the runbook for the project lead's desk (this lane never touches PC 1).
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
(cherry picked from commit 0d5fc6d258dee4774ebe7ea760736c9f05026d06)
