chore(plugin-kit): 0.4.2 — publish the art scan fix, which no plugin can pick up otherwise

The Steam scanner is `@punktfunk/plugin-steam`, in its own repo, and it builds
with `--external '@punktfunk/*'` — so `findLocalArtFile` is resolved from the
registry at install time, not bundled. Until the kit cuts a version, every host
keeps resolving 0.4.1 and keeps missing the covers.

Same shape as the `icon` field at 0.4.1: kit change, out-of-tree producers, and
nothing in this repo says so. Nothing but the version moves here.

plugin-kit/package.json

@@ -1,6 +1,6 @@
 {
 	"name": "@punktfunk/plugin-kit",
-	"version": "0.4.1",
+	"version": "0.4.2",
 	"description": "Effect-based framework for punktfunk plugins: lifecycle runtime, config/state, sync engine, UI serving, CLI scaffold, and browser helpers.",
 	"type": "module",
 	"license": "MIT OR Apache-2.0",