All CEK primitives (cek-step-loop/cek-resume/make-cek-state/cek-suspended?/
cek-io-request/cek-terminal?/cek-value) were already registered in sx-browser.js.
Root cause of test failure: (import (sx coroutines)) creates an io-suspended
state when the library isn't pre-loaded; overridden cekRun throws on suspension.
Fix: pre-load spec/signals.sx + spec/coroutines.sx before test files run.
17/17 coroutine tests pass in JS. 1965/2500 total (+25 vs 1940 baseline),
zero new failures.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
giles
b78e06a772