CAT-BI1: mesh-build-image publishes and copies through container-image-registry

A trunk image is written as an OCI layout and published by the seat's
publish and publish-part, only the parts the holder lacks; an upstream copy is
the seat's mirror, ended on the holder's published or refused. The module
holds no registry address: artifact-store, files/registry and the copier go,
and the step answers the seat's reference.

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig

modules/mesh-build-image/module.json

@@ -52,9 +52,17 @@
   "requires": [
     "forge-account",
     "rootless-image-build",
-    "artifact-store",
     "node-tools"
   ],
+  "invokes": [
+    "seat:container-image-registry.publish",
+    "seat:container-image-registry.publish-part",
+    "seat:container-image-registry.mirror"
+  ],
+  "consumes": [
+    "container-image-registry.published",
+    "container-image-registry.refused"
+  ],
   "own-secrets": {
     "broker": "${dir:state}/broker"
   },
@@ -142,14 +150,6 @@
       "mode": "0644",
       "template": "files/gitconfig"
     },
-    {
-      "id": "registry",
-      "type": "file",
-      "path": "${dir:state}/registry",
-      "owner": "mesh-build-image",
-      "mode": "0644",
-      "template": "files/registry"
-    },
     {
       "id": "git",
       "type": "package",