Release 0.5.0 at 0ae5461.
Minor (breaking) release: adopts polyengine's A22 protocol/runtime split. The published host module now depends on @polyengine/protocol@^0.2.2 only — it no longer names @polyengine/runtime at all, so consumers stop receiving the engine through this package (runtime selection stays with the deploying application), and lockstep engine releases that leave the host ABI untouched no longer touch this package. The repo's own legs consume the polyengine v0.5.0 release.
Still 0.x/unstable, but caret-honest: releases within a minor line stay compatible; breaking changes bump the minor.