Retracted: v0.4.0 was tagged on the wrong commit (a small CI-permissions change that
branched off an older main, missing the release's actual content) and
published to the module proxy before the mistake was caught. The proxy
treats published versions as immutable, so the tag itself cannot be
corrected in place. The intended v0.4.0 content ships as v0.4.1.
Package main demonstrates a monolithic Modulex deployment: every feature
module is registered in-process and dependencies are wired directly to local
implementations.