feat: GraphRAG — LLM 抽三元组建 Neo4j 图谱 + 混合检索加图谱第三路

混合检索从 2 路(向量+全文)升级为 3 路(+图谱)。入库时 LLM 抽实体/关系建
Neo4j 图，检索时图谱路(实体关联三元组)融进 RRF；UI 可视化图谱。

- mcp-go rag: chat.go(OpenAI 兼容非流式 chat 客户端,抽取用) + graph.go(neo4j-go-driver
  连接 + LLM 抽三元组 + MERGE 实体/关系 + 图谱召回/全量三元组) + rag.go(Config 结构;
  graph+chat 路;Ingest 加 抽实体/写Neo4j 阶段;Search 三路 RRF 融合;SetChat 热更新)
- mcp-go: Neo4j env(默认 neo4j://localhost:7687, neo4j/sundynix);订阅 chat 控制面配置
  (复用 DeepSeek 做抽取);新工具 kb_graph(返回三元组)
- gateway: GET /api/v1/kb/graph;frontend KbView 知识图谱面板(实体—关系→实体)
- 验证: 全模块 build✓ + e2e PASS; live——入库'sundynix用Milvus...'→DeepSeek 抽 4 三元组
  →Neo4j(8 实体);检索三路融合 向量=4 全文=2 图谱=1;浏览器图谱面板渲染 4 三元组
- 边界: 实体链接用 CONTAINS 朴素匹配(可升级 LLM 查询实体抽取);全文/图谱重启随入库重建

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

sundynix-desktop/frontend/src/lib/api.ts

@@ -105,6 +105,20 @@ export interface KbHit {
   score: number;
 }
 
+export interface Triple {
+  s: string;
+  p: string;
+  o: string;
+}
+
+// graphKb: GET /api/v1/kb/graph —— 取某知识库的图谱三元组（→ mcp-go kb_graph，Neo4j）。
+export async function graphKb(kb: string): Promise<Triple[]> {
+  const res = await fetch(`${GATEWAY}/api/v1/kb/graph?kb=${encodeURIComponent(kb)}`);
+  const data = (await res.json()) as { triples?: Triple[]; error?: string };
+  if (!res.ok) throw new Error(data.error ?? `graph failed: ${res.status}`);
+  return data.triples ?? [];
+}
+
 // searchKb: POST /api/v1/kb/search，检索台查询（→ mcp-go kb_search，带分数）。
 export async function searchKb(kb: string, q: string, topK = 5): Promise<KbHit[]> {
   const res = await fetch(`${GATEWAY}/api/v1/kb/search`, {

sundynix-desktop/frontend/src/views/KbView.tsx

@@ -1,5 +1,5 @@
 import { useRef, useState } from "react";
-import { ingestKb, ingestFile, streamIngest, searchKb, type IngestEvent, type KbHit } from "../lib/api";
+import { ingestKb, ingestFile, streamIngest, searchKb, graphKb, type IngestEvent, type KbHit, type Triple } from "../lib/api";
 
 interface IngestLog {
   t: string;
@@ -29,6 +29,15 @@ export function KbView() {
   const [hits, setHits] = useState<KbHit[] | null>(null);
   const [searching, setSearching] = useState(false);
   const [err, setErr] = useState("");
+  const [graph, setGraph] = useState<Triple[] | null>(null);
+
+  const onGraph = async () => {
+    try {
+      setGraph(await graphKb(kb));
+    } catch (e) {
+      setErr((e as Error).message);
+    }
+  };
 
   const stamp = () => new Date().toLocaleTimeString();
   const ingesting = prog?.active ?? false;
@@ -234,7 +243,7 @@ export function KbView() {
             </button>
           </div>
           {err && <p className="mt-2 text-xs text-rose-600">✗ {err}</p>}
-          <ul className="mt-3 flex-1 space-y-2 overflow-auto">
+          <ul className="mt-3 max-h-[40%] space-y-2 overflow-auto">
             {hits === null && <li className="text-xs text-gray-400">输入查询后展示命中片段与分数。</li>}
             {hits !== null && hits.length === 0 && (
               <li className="text-xs text-gray-400">无命中（知识库为空或 RAG 未配置）。</li>
@@ -250,6 +259,27 @@ export function KbView() {
               </li>
             ))}
           </ul>
+
+          {/* 知识图谱（Neo4j / GraphRAG） */}
+          <div className="mt-3 flex items-center justify-between border-t pt-2">
+            <h3 className="text-xs font-semibold text-gray-600">知识图谱（Neo4j）</h3>
+            <button onClick={onGraph} className="rounded border px-2 py-0.5 text-xs hover:bg-gray-50">
+              查看图谱
+            </button>
+          </div>
+          <ul className="mt-2 flex-1 space-y-1 overflow-auto">
+            {graph === null && <li className="text-[11px] text-gray-400">点「查看图谱」展示入库抽取的实体关系。</li>}
+            {graph !== null && graph.length === 0 && (
+              <li className="text-[11px] text-gray-400">该库暂无图谱（需配置 chat 模型 + 入库触发抽取）。</li>
+            )}
+            {graph?.map((t, i) => (
+              <li key={i} className="flex items-center gap-1 text-[11px]">
+                <span className="rounded bg-amber-100 px-1.5 py-0.5 text-amber-700">{t.s}</span>
+                <span className="text-gray-400">—{t.p}→</span>
+                <span className="rounded bg-emerald-100 px-1.5 py-0.5 text-emerald-700">{t.o}</span>
+              </li>
+            ))}
+          </ul>
         </section>
       </div>
     </div>