fix: allow empty followerIdentifiers to avoid blocking openclaw CLI

An empty followerIdentifiers array caused a fatal validation error during
plugin registration, which prevented all openclaw CLI commands from running.

plugin/core/config.ts

@@ -59,8 +59,8 @@ export function validateYonexusServerConfig(raw: unknown): YonexusServerConfig {
         .filter((value) => value.length > 0)
     : [];
 
-  if (!Array.isArray(rawIdentifiers) || followerIdentifiers.length === 0) {
-    issues.push("followerIdentifiers must contain at least one non-empty identifier");
+  if (!Array.isArray(rawIdentifiers)) {
+    issues.push("followerIdentifiers must be an array");
   }
 
   if (new Set(followerIdentifiers).size !== followerIdentifiers.length) {

plugin/openclaw.plugin.json

@@ -19,6 +19,6 @@
       "listenPort": { "type": "number" },
       "publicWsUrl": { "type": "string" }
     },
-    "required": ["followerIdentifiers", "notifyBotToken", "adminUserId", "listenPort"]
+    "required": ["notifyBotToken", "adminUserId", "listenPort"]
   }
 }