feat(registry): 插件与应用关系契约4.2 / plugin and application contract (#10)

* feat(registry): 增加插件贡献与应用依赖的4.2契约

* fix(registry): preserve legacy App manifests for published clients

---------

Co-authored-by: yi-ge <6657330+yi-ge@users.noreply.github.com>

entries/ragflow/catalog-metadata.v1.json

@@ -76,6 +76,10 @@
   },
   "spec": {
     "kind": "app",
-    "category": "rag"
+    "category": "rag",
+    "productKind": "application",
+    "entrypointKinds": [
+      "agent"
+    ]
   }
 }