feat: 完善知识图谱交互与 Agent/线程持久化

- 知识图谱画布、侧边栏、详情面板交互优化，新增图谱相关 API 与 hooks
- Agent 卡片与详情面板调整，对话页面重构
- 线程元数据持久化增强（base/memory/sql），knowledge 仓储与导出补充
- 网关路由 agents/knowledge/threads 同步更新

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/components/knowledge-graph/GraphDetailPanel.tsx

@@ -1,4 +1,5 @@
 import {
+  Ban,
   Compass,
   Crosshair,
   EyeOff,
@@ -56,6 +57,7 @@ interface GraphDetailPanelProps {
   onViewSource: (noteId: string) => void;
   onLocate: (id: string) => void;
   onHide: (id: string) => void;
+  onBlacklist: (id: string) => void;
   onPickNeighbor: (id: string) => void;
   onExpandNode: (id: string) => void;
   onSetExploreRoot: (id: string) => void;
@@ -213,6 +215,14 @@ function DetailBody(props: GraphDetailPanelProps & { node: GraphNode }) {
         >
           <EyeOff size={14} /> 隐藏节点
         </button>
+        <button
+          type="button"
+          className="kg-icon-button"
+          title="加入黑名单后该节点将不再出现在图谱中,可在左侧「图谱黑名单」中移除"
+          onClick={() => props.onBlacklist(node.id)}
+        >
+          <Ban size={14} /> 加入黑名单
+        </button>
         {props.explore ? (
           <>
             <button