The empty-env hardening wiped the one variable the UNBUILT worker's
loader depends on: tsx finds a tsconfig by searching up from the
worker's cwd, and a parent running outside the repo (the ACP snapshot
harness pins the repo tsconfig through TSX_TSCONFIG_PATH exactly
because its child cwd is a temp dir) lost the dsh-* paths map - the
worker then resolved workspace imports to unbuilt lib/ bundles and died
on CI with ERR_MODULE_NOT_FOUND (green locally only because stale built
lib/ masked the wrong resolution).
Forward exactly that variable when the parent carries it - loader
plumbing, not a secret; the built shape stays fully empty - and pin the
whole contract with an escape-based test: the worker env is exactly
{TSX_TSCONFIG_PATH}, the credential canary still never crosses.