v4.9.4

Fixed

• Plugin upgrades now fail closed before cache replacement when the staged
  artifact is incomplete. Before an upgrade can swap the live cache, the
  updater validates every hook, plugin manifest, and MCP entrypoint in the
  staged copy; missing or swapped targets leave the existing cache and
  registry unchanged. The release gate runs the same checker and additionally
  confirms every target is present in the npm-packed artifact.
• Release audits no longer inherit an unsafe or unbounded npm cache. The
  consumer audit uses a private temporary cache and bounded subprocess
  lifetimes, reporting a controlled failure instead of hanging or being
  affected by root-owned cache state.
• Pre-release coverage now protects the updater's own checker. A copied
  or incomplete updater refuses to install a plugin archive when its trusted
  artifact-integrity checker is absent.
• The npm package ships the checker's one dependency. The
  artifact-integrity checker imports scripts/lib/npm-bin.mjs, which the
  package did not include, so the checker could not load from an npm install
  and memesh upgrade-plugin — which prefers the npm-installed copy of the
  updater — would have refused every upgrade. A test now unpacks the real
  tarball and runs the checker from it. The checker also rejects a symlinked
  directory above a hook target, not only a symlinked file.