feat: 移除 etcdutl 引用，增加 ctr/nerdctl 示例，实现 Agent 断点续传

- AI Agent Prompt 移除不存在的 etcdutl 命令引用
- Prompt 增加 containerd(ctr/nerdctl) 和 Linux 基础调优命令示例
- processing_runs 表新增 context_json 字段，保存 Agent 执行上下文
- 每次命令执行后自动保存上下文到 DB

backend/main.py

@@ -22,7 +22,8 @@ from backend.diagnosis import (
 from backend.ai_agent import (
     analyze_with_ai, chat_with_ai,
     analyze_with_ai_stream, chat_with_ai_stream,
-    run_diagnostic_agent, resume_diagnostic_agent, take_pending_approval,
+    run_diagnostic_agent, resume_diagnostic_agent, resume_from_context,
+    take_pending_approval,
 )
 from backend.agent_tools import execute_command
 from backend.history_store import HistoryStore
@@ -329,6 +330,8 @@ async def agent_diagnose_stream(question: str = "", execution_mode: str = "ai"):
                 question=question,
                 max_steps=0,
                 execution_mode=execution_mode,
+                run_id=run_id,
+                history_store=history_store,
             ):
                 history_store.append_event(run_id, event.get("type", "event"), {k: v for k, v in event.items() if k != "type"})
                 if event.get("type") == "final":
@@ -409,6 +412,53 @@ async def execute_approved_agent_command(req: AgentApprovalRequest):
     )
 
 
+@app.get("/api/agent/resume-stream/{run_id}")
+async def agent_resume_stream(run_id: str):
+    """从 DB 上下文恢复 Agent 诊断，不重跑历史命令，直接继续诊断。"""
+    ctx = history_store.get_context(run_id)
+    if ctx is None:
+        raise HTTPException(status_code=404, detail="该运行记录不存在或不支持断点续传")
+    ctx.pop("report", None)  # get_context 已经注入了 report
+
+    async def event_generator():
+        yield f"data: {json.dumps({'type': 'start', 'mode': ctx.get('execution_mode', 'ai'), 'run_id': run_id, 'resumed': True}, ensure_ascii=False)}\n\n"
+        final_status = "completed"
+        summary = ""
+        try:
+            async for event in resume_from_context(
+                ctx=ctx,
+                run_id=run_id,
+                history_store=history_store,
+            ):
+                history_store.append_event(run_id, event.get("type", "event"), {k: v for k, v in event.items() if k != "type"})
+                if event.get("type") == "final":
+                    summary = event.get("content", "")
+                elif event.get("type") == "error":
+                    final_status = "failed"
+                    summary = event.get("message", "")
+                elif event.get("type") in {"manual_command", "approval_required"}:
+                    final_status = "waiting"
+                    if event.get("type") == "approval_required":
+                        from backend.ai_agent import _PENDING_APPROVALS
+                        pending = _PENDING_APPROVALS.get(event.get("approval_id"))
+                        if pending is not None:
+                            pending["run_id"] = run_id
+                yield f"data: {json.dumps(event, ensure_ascii=False)}\n\n"
+            history_store.finish_run(run_id, final_status, summary)
+            yield f"data: {json.dumps({'type': 'done', 'run_id': run_id}, ensure_ascii=False)}\n\n"
+        except Exception as exc:
+            message = f"断点续传诊断失败: {exc}"
+            history_store.append_event(run_id, "error", {"message": message})
+            history_store.finish_run(run_id, "failed", message)
+            yield f"data: {json.dumps({'type': 'error', 'message': message}, ensure_ascii=False)}\n\n"
+
+    return StreamingResponse(
+        event_generator(),
+        media_type="text/event-stream",
+        headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
+    )
+
+
 @app.post("/api/chat")
 async def chat(req: ChatRequest):
     """AI 多轮对话 (非流式，兼容旧接口)"""