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/history_store.py

@@ -53,6 +53,7 @@ class HistoryStore:
                     summary TEXT NOT NULL DEFAULT '',
                     started_at TEXT NOT NULL,
                     finished_at TEXT,
+                    context_json TEXT NOT NULL DEFAULT '',
                     FOREIGN KEY(diagnosis_id) REFERENCES diagnoses(id) ON DELETE CASCADE
                 );
                 CREATE INDEX IF NOT EXISTS idx_runs_diagnosis ON processing_runs(diagnosis_id, started_at);
@@ -68,6 +69,15 @@ class HistoryStore:
                     UNIQUE(run_id, sequence)
                 );
             """)
+            # 兼容旧表：确保 context_json 列存在
+            self._ensure_column(db, "processing_runs", "context_json", "TEXT NOT NULL DEFAULT ''")
+
+    def _ensure_column(self, db, table: str, column: str, col_def: str):
+        try:
+            db.execute(f"ALTER TABLE {table} ADD COLUMN {column} {col_def}")
+        except sqlite3.OperationalError as e:
+            if "duplicate column" not in str(e).lower():
+                raise
 
     def save_diagnosis(self, diagnosis: dict, report: str) -> str:
         record_id = uuid.uuid4().hex
@@ -130,6 +140,11 @@ class HistoryStore:
                     {"type": event["type"], "created_at": event["created_at"], **json.loads(event["payload_json"])}
                     for event in event_rows
                 ]
+                run["context_json"] = run.get("context_json") or ""
+                if run["context_json"]:
+                    run["context"] = json.loads(run["context_json"])
+                else:
+                    run["context"] = None
                 runs.append(run)
         return {
             "id": row["id"], "created_at": row["created_at"],
@@ -152,6 +167,30 @@ class HistoryStore:
             )
         return run_id
 
+    def update_context(self, run_id: str, context: dict):
+        """保存/更新 Agent 执行上下文到 processing_runs，支持断点续传。"""
+        with self._connect() as db:
+            db.execute(
+                "UPDATE processing_runs SET context_json = ? WHERE id = ?",
+                (json.dumps(context, ensure_ascii=False), run_id),
+            )
+
+    def get_context(self, run_id: str) -> Optional[dict]:
+        """读取 Agent 执行上下文，如果不存在或为空则返回 None。"""
+        with self._connect() as db:
+            row = db.execute(
+                "SELECT context_json, diagnosis_id, report FROM processing_runs pr JOIN diagnoses d ON pr.diagnosis_id = d.id WHERE pr.id = ?",
+                (run_id,),
+            ).fetchone()
+            if row is None:
+                return None
+            ctx_str = row["context_json"] or ""
+            if not ctx_str:
+                return None
+            ctx = json.loads(ctx_str)
+            ctx["report"] = row["report"]
+            return ctx
+
     def append_event(self, run_id: str, event_type: str, payload: dict):
         with self._connect() as db:
             sequence = db.execute(