fix(teacher): 区分读取额度与上下文失效

electron/coding-teacher/cloud-runner.ts

@@ -300,18 +300,20 @@ export function prepareCloudTeacher(
                 'teacher_interaction_unsupported',
                 '智能体请求了当前面板不支持的交互，请联系运营调整该智能体。'
               );
-            if (
-              pending.context_id !== requestId ||
-              !Array.isArray(pending.calls) ||
-              !pending.calls.length ||
-              pending.calls.length > 32 ||
-              ++rounds > 6
-            )
+            if (pending.context_id !== requestId)
               throw new TeacherError(
                 409,
                 'teacher_context_expired',
                 '智能体读取请求已失效，请重新提问。'
               );
+            if (!Array.isArray(pending.calls) || !pending.calls.length || pending.calls.length > 32)
+              throw new TeacherError(502, 'teacher_protocol_invalid', '智能体读取请求格式无效，请重试。');
+            if (++rounds > 6)
+              throw new TeacherError(
+                409,
+                'teacher_read_limit',
+                '智能体已达到本次读取上限，但尚未完成回答。请缩小检查范围后重试。'
+              );
             onProgress('正在读取项目与会话…');
             const results = [];
             for (const raw of pending.calls) {