feat(knowledge): 阶段三 知识治理 + 阶段四 图谱增强

阶段三（治理）:
- sensitive.py：写入前脱敏 token/密钥/手机号/身份证/邮箱（sensitive_redaction_enabled）
- 版本快照：更新前写 knowledge_note_versions；GET /notes/{id}/versions
- dedup.py：标题/摘要 Jaccard + 内容哈希查重；GET /duplicates、POST /merge（来源并入主条目、重复项归档）
- auto_ingest.py：独立后台队列/线程沉淀，不阻塞问答；中间件 after_agent 在 auto_ingest_enabled 时入队；价值判断（最小字符）+ skip_existing 去重；自动沉淀落 draft 待审

阶段四（图谱）:
- LLM 抽取 entities/relations；service 存 knowledge_entities/knowledge_relations 并连边
- exporter.build_graph 支持实体节点 + note→entity/entity→entity 边；graph.html/json 增强
- GET /api/knowledge/graph 返回产品图谱数据

前端：知识库页「查重合并」对话框 + 相关 api/hooks
配置：sensitive_redaction_enabled / dedup_similarity_threshold / entity_extraction_enabled
测试：tests/test_knowledge.py 20 passed

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

frontend-web/src/core/knowledge/api.ts

@@ -131,3 +131,61 @@ export async function exportKnowledgeGraph() {
 export function knowledgeExportFileUrl(filename: string) {
   return `${baseUrl()}/export/files/${encodeURIComponent(filename)}`;
 }
+
+// --- phase 2/3/4 ---
+
+export interface KnowledgeVersion {
+  id: string;
+  note_id: string;
+  title: string;
+  summary?: string | null;
+  content_md: string;
+  status: string;
+  tags: string[];
+  edited_by?: string | null;
+  created_at?: string | null;
+}
+
+export async function listNoteVersions(noteId: string) {
+  const res = await parseResponse<{ items: KnowledgeVersion[] }>(
+    await apiFetch(`${baseUrl()}/notes/${encodeURIComponent(noteId)}/versions`),
+  );
+  return res.items;
+}
+
+export interface DuplicateGroup {
+  primary: { id: string; title: string | null };
+  duplicates: Array<{ id: string; title: string | null; score: number }>;
+}
+
+export async function listDuplicates() {
+  const res = await parseResponse<{ groups: DuplicateGroup[] }>(
+    await apiFetch(`${baseUrl()}/duplicates`),
+  );
+  return res.groups;
+}
+
+export async function mergeKnowledgeNotes(primaryId: string, duplicateIds: string[]) {
+  return parseResponse<{ note: KnowledgeNote }>(
+    await apiFetch(`${baseUrl()}/merge`, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ primary_id: primaryId, duplicate_ids: duplicateIds }),
+    }),
+  );
+}
+
+export async function reindexKnowledge() {
+  return parseResponse<{ reindexed: number; embedding_enabled: number }>(
+    await apiFetch(`${baseUrl()}/reindex`, { method: "POST" }),
+  );
+}
+
+export interface KnowledgeGraph {
+  nodes: Array<{ id: string; type: string; label: string; category?: string | null }>;
+  edges: Array<{ id: string; source: string; target: string; label: string; weight: number }>;
+}
+
+export async function getKnowledgeGraph() {
+  return parseResponse<KnowledgeGraph>(await apiFetch(`${baseUrl()}/graph`));
+}

frontend-web/src/core/knowledge/hooks.ts

@@ -12,7 +12,9 @@ import {
   getKnowledgeNote,
   ingestThread,
   ingestThreadsBatch,
+  listDuplicates,
   listKnowledgeNotes,
+  mergeKnowledgeNotes,
   searchKnowledge,
   updateKnowledgeNote,
 } from "./api";
@@ -85,5 +87,19 @@ export function useKnowledgeActions() {
       onSuccess: invalidate,
     }),
     exportGraph: useMutation({ mutationFn: exportKnowledgeGraph }),
+    merge: useMutation({
+      mutationFn: ({ primaryId, duplicateIds }: { primaryId: string; duplicateIds: string[] }) =>
+        mergeKnowledgeNotes(primaryId, duplicateIds),
+      onSuccess: invalidate,
+    }),
   };
 }
+
+export function useKnowledgeDuplicates(enabled: boolean) {
+  return useQuery({
+    queryKey: [...ROOT_KEY, "duplicates"],
+    queryFn: listDuplicates,
+    enabled,
+    refetchOnWindowFocus: false,
+  });
+}