fix: remove invalid keys from marketplace.json plugins entry

The plugins array entries only support 'name' and 'source' fields.
The 'version' and 'description' keys cause schema validation failures
during the marketplace review process.

.claude-plugin/marketplace.json

@@ -9,8 +9,6 @@
   "plugins": [
     {
       "name": "understand-anything",
-      "description": "Multi-agent codebase analysis with interactive dashboard, guided tours, and skill commands",
-      "version": "2.2.0",
       "source": "./understand-anything-plugin"
     }
   ]