fix: 修复4个已知BUG — P1 ChatList/P2 错误密码/P3 Copilot崩溃/P3超管entrypoint

P1: ChatList.vue — 添加 conversationStats watch fallback，检测 stats>0
   但 chatList 为空时自动触发 fetchConversations
P2: api.js parseAPIErrorResponse — 处理 error 字段为对象时提取 .message
P3: CopilotContainer.vue — activeAssistant 判空保护
P3: 新建 super_admin.html + vite.config.ts rewrite 规则
    (注：entrypoint 仅含样式，Vue应用代码待补)
防御: NotificationTable.vue — 可选链保护 primary_actor.meta 路径

frontend/app/javascript/dashboard/store/utils/api.js

@@ -92,12 +92,27 @@ export const parseAPIErrorResponse = error => {
     return error?.response?.data?.message;
   }
   if (error?.response?.data?.error) {
-    return error?.response?.data?.error;
+    // error could be a string or an object with a message property
+    if (typeof error.response.data.error === 'string') {
+      return error.response.data.error;
+    }
+    if (error.response.data.error?.message) {
+      return error.response.data.error.message;
+    }
+    return JSON.stringify(error.response.data.error);
   }
   if (error?.response?.data?.errors) {
-    return error?.response?.data?.errors[0];
+    const first = error.response.data.errors;
+    if (Array.isArray(first)) {
+      return first[0];
+    }
+    return first;
   }
-  return error;
+  // Fallback: return a useful default message rather than the raw error object
+  if (error?.message && typeof error.message === 'string') {
+    return error.message;
+  }
+  return 'Request failed. Please try again.';
 };
 
 export const throwErrorMessage = error => {