refactor: change agent cloud data permission to cloud variables only

- Rename permission from '查看云端数据' to '查看云端变量'
- Remove cloud constants API and page for agents
- Add cloud variable records API for agents (stream type)
- Add agent cloud-variables page with full variable details
- Add agent cloud-variable records page (read-only)
- Update navigation from cloud-data to cloud-variables
- Update i18n keys: cloudData -> cloudVariables
- Backend returns var_type, default_value, max_records etc.
- Records page supports dynamic columns and date filtering

frontend/src/plugins/i18n/zh.json

@@ -924,7 +924,7 @@
         "maxApiCalls": "API调用次数/月",
         "maxApiCallsPlaceholder": "-1表示不限",
         "allowAgent": "代理权限",
-        "allowCloudData": "云端数据",
+        "allowCloudData": "云端变量",
         "allowDynamicCode": "云端函数",
         "allowEmail": "邮件功能",
         "allowExtension": "扩展接口",
@@ -1242,7 +1242,7 @@
         "cardsCount": "生成卡密",
         "childAgentsCount": "下级代理",
         "canCreateAgent": "创建代理权限",
-        "canViewCloudData": "云端数据权限",
+        "canViewCloudData": "查看云端变量权限",
         "balance": "余额",
         "totalConsumption": "消费",
         "createdAt": "注册时间",
@@ -2888,27 +2888,49 @@
         "generateNow": "立即生成"
       }
     },
-    "cloudData": {
-      "title": "云端数据",
-      "description": "查看云端变量和常量数据（只读）",
-      "variables": "云端变量",
-      "constants": "云端常量",
-      "applications": "应用数量",
-      "dataList": "数据列表",
-      "readOnlyHint": "只读模式，数据不可编辑",
-      "allApps": "全部应用",
+    "cloudVariables": {
+      "title": "云端变量",
+      "description": "查看云端变量数据（只读）",
+      "totalVariables": "变量总数",
+      "appScopeVariables": "应用级变量",
+      "userScopeVariables": "用户级变量",
+      "appCount": "应用数量",
       "noVariables": "暂无云端变量数据",
-      "noConstants": "暂无云端常量数据",
+      "appScope": "应用级",
+      "userScope": "用户级",
       "statusActive": "启用",
       "statusInactive": "禁用",
-      "readOnlyNote": "只读模式 - 当前数据仅供查看，无法进行编辑操作",
+      "viewRecords": "查看记录",
+      "application": "应用",
+      "scope": "作用域",
+      "types": {
+        "integer": "整数",
+        "decimal": "小数",
+        "string": "字符串",
+        "binary": "二进制",
+        "stream": "列表"
+      },
       "columns": {
-        "name": "名称",
-        "application": "应用",
+        "key": "变量名",
+        "defaultValue": "默认值",
+        "type": "类型",
         "scope": "作用域",
-        "value": "值",
+        "application": "应用",
         "status": "状态",
         "createdAt": "创建时间"
+      },
+      "records": {
+        "title": "变量记录",
+        "description": "变量 {key} 的记录列表",
+        "totalRecords": "记录总数",
+        "maxRecordsLabel": "最大记录数",
+        "unlimited": "无限制",
+        "user": "用户",
+        "data": "数据",
+        "createdAt": "创建时间",
+        "searchPlaceholder": "搜索记录...",
+        "startDate": "开始日期",
+        "endDate": "结束日期"
       }
     }
   },
@@ -2933,7 +2955,7 @@
       "apiCalls": "{count}次/月 API调用",
       "unlimitedApiCalls": "无限API调用",
       "agent": "代理权限",
-      "cloudData": "云端数据功能",
+      "cloudData": "云端变量功能",
       "dynamicCode": "云端函数功能",
       "email": "邮件功能",
       "extension": "扩展接口功能",