refactor: deduplicate reply payload helpers

scripts/lib/plugin-sdk-entrypoints.json

@@ -13,6 +13,7 @@
   "setup-tools",
   "config-runtime",
   "reply-runtime",
+  "reply-payload",
   "channel-runtime",
   "interactive-runtime",
   "infra-runtime",
@@ -88,6 +89,7 @@
   "channel-config-schema",
   "channel-lifecycle",
   "channel-policy",
+  "channel-send-result",
   "group-access",
   "directory-runtime",
   "json-store",