feat(knowledge): 图谱跟随删除 + 笔记页展示实体 + 标签美化

图谱不随删除变化的根因：实体/关系删除时从不清理，build_graph 又把所有实体
都当节点，导致已删笔记的实体（六福珠宝/COMEX/CM助手…）永久残留。

- build_graph 只保留被「活笔记」提及的实体，孤儿实体节点不再出现（render 层兜底，
  历史脏数据无需迁移即生效）
- delete_note 删除时 clear_note_relations + prune_orphan_entities，DB 同步收敛
- get_note 返回 entities（repo.list_note_entities），笔记详情页展示实体
- 前端：实体按类型彩色 chip 展示（人物/机构/概念/产品/技术/地区…），标签改为 pill 样式
- 测试：get_note 返回实体 + 删除后图谱与实体表同步收敛

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

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

@@ -20,6 +20,11 @@ export interface KnowledgeSource {
   created_at?: string | null;
 }
 
+export interface KnowledgeEntity {
+  name: string;
+  entity_type?: string | null;
+}
+
 export interface KnowledgeNote {
   id: string;
   title: string;
@@ -37,6 +42,7 @@ export interface KnowledgeNote {
   created_at?: string | null;
   updated_at?: string | null;
   tags: string[];
+  entities?: KnowledgeEntity[];
   sources?: KnowledgeSource[];
 }
 

frontend-web/src/pages/KnowledgeBasePage.tsx

@@ -72,6 +72,25 @@ function actorLabel(name?: string | null, id?: string | null): string {
   return "—";
 }
 
+const ENTITY_TYPE_META: Record<string, { label: string; className: string }> = {
+  person: { label: "人物", className: "bg-rose-50 text-rose-700 border-rose-200 dark:bg-rose-500/15 dark:text-rose-300 dark:border-rose-500/30" },
+  org: { label: "机构", className: "bg-blue-50 text-blue-700 border-blue-200 dark:bg-blue-500/15 dark:text-blue-300 dark:border-blue-500/30" },
+  product: { label: "产品", className: "bg-violet-50 text-violet-700 border-violet-200 dark:bg-violet-500/15 dark:text-violet-300 dark:border-violet-500/30" },
+  technology: { label: "技术", className: "bg-cyan-50 text-cyan-700 border-cyan-200 dark:bg-cyan-500/15 dark:text-cyan-300 dark:border-cyan-500/30" },
+  concept: { label: "概念", className: "bg-amber-50 text-amber-700 border-amber-200 dark:bg-amber-500/15 dark:text-amber-300 dark:border-amber-500/30" },
+  region: { label: "地区", className: "bg-emerald-50 text-emerald-700 border-emerald-200 dark:bg-emerald-500/15 dark:text-emerald-300 dark:border-emerald-500/30" },
+  country: { label: "国家", className: "bg-emerald-50 text-emerald-700 border-emerald-200 dark:bg-emerald-500/15 dark:text-emerald-300 dark:border-emerald-500/30" },
+};
+
+function entityMeta(type?: string | null) {
+  return (
+    ENTITY_TYPE_META[(type || "").toLowerCase()] ?? {
+      label: "其他",
+      className: "bg-slate-100 text-slate-600 border-slate-200 dark:bg-slate-700/40 dark:text-slate-300 dark:border-slate-600",
+    }
+  );
+}
+
 function useDebounced<T>(value: T, delay = 350): T {
   const [debounced, setDebounced] = useState(value);
   useEffect(() => {
@@ -542,17 +561,44 @@ function NoteDetail({ noteId }: { noteId: string }) {
             </div>
           ) : (
             <>
-              <h1 className="mb-2 text-xl font-semibold">{note.title}</h1>
-              <div className="mb-3 flex flex-wrap gap-1">
-                {note.tags.map((tag) => (
-                  <span
-                    key={tag}
-                    className="bg-muted text-muted-foreground rounded px-1.5 py-0.5 text-xs"
-                  >
-                    #{tag}
-                  </span>
-                ))}
-              </div>
+              <h1 className="mb-3 text-xl font-semibold">{note.title}</h1>
+
+              {note.tags.length > 0 ? (
+                <div className="mb-2 flex flex-wrap items-center gap-1.5">
+                  {note.tags.map((tag) => (
+                    <span
+                      key={tag}
+                      className="border-primary/20 bg-primary/5 text-primary/90 hover:bg-primary/10 inline-flex items-center rounded-full border px-2.5 py-0.5 text-xs font-medium transition-colors"
+                    >
+                      #{tag}
+                    </span>
+                  ))}
+                </div>
+              ) : null}
+
+              {note.entities && note.entities.length > 0 ? (
+                <div className="mb-4 flex flex-wrap items-center gap-1.5">
+                  <span className="text-muted-foreground mr-0.5 text-xs">实体</span>
+                  {note.entities.map((ent) => {
+                    const meta = entityMeta(ent.entity_type);
+                    return (
+                      <span
+                        key={`${ent.name}-${ent.entity_type ?? ""}`}
+                        className={cn(
+                          "inline-flex items-center gap-1 rounded-full border px-2 py-0.5 text-xs font-medium",
+                          meta.className,
+                        )}
+                        title={meta.label}
+                      >
+                        <span className="size-1.5 rounded-full bg-current opacity-60" />
+                        {ent.name}
+                        <span className="opacity-60">{meta.label}</span>
+                      </span>
+                    );
+                  })}
+                </div>
+              ) : null}
+
               <MarkdownRenderer
                 content={note.content_md}
                 wikiLinks={wikiLinks}