refactor(marker): migrate to repo + build groups

Replace flat layout + native with repo: { type } + build: { from, type }
matching the updated socket-wheelhouse schema.

Author: jdalton

.config/socket-wheelhouse.json

@@ -2,8 +2,8 @@
   "$schema": "./socket-wheelhouse-schema.json",
   "schemaVersion": 1,
   "repoName": "socket-lib",
-  "layout": "single-package",
-  "native": "none",
+  "repo": { "type": "single-package" },
+  "build": { "from": "npm-registry", "type": "js" },
   "lint": {
     "profile": "rich"
   }