feat(coding): keep one ongoing conversation per delivered agent

electron/coding-teacher/context.ts

@@ -60,7 +60,8 @@ export function teacherHistoryMessages(history: TeacherRequest[]): TeacherSource
   return history.filter(request => request.status === 'completed').flatMap((request): TeacherSourceMessage[] => [
     ...(request.intent === 'check-in' ? [] : [{
       id: 'teacher:' + request.id + ':user', role: 'user' as const,
-      text: [...request.references.map(ref => '明确引用：\n' + ref.text), request.text].join('\n\n'),
+      text: [...(request.projectId ? ['当时的项目：' + (request.projectName ?? request.projectId)] : []),
+        ...request.references.map(ref => '明确引用：\n' + ref.text), request.text].join('\n\n'),
     }]),
     {
       id: 'teacher:' + request.id + ':assistant', role: 'assistant' as const,