feat(web): 播报板节点详情展示上游节点信息与锚定资产

上游/下游节点从只显示 id 改为悬停弹出节点名片(类型/状态/来源/时间/摘要/payload);
展开时顺带展示该节点锚定的资产(类型标签 + 可辨识文本)。

服务端 /exploration/nodes 新增 assets 字段(节点id→资产),读 exploration_anchors
并复用发现列表的资产打标逻辑;同页节点互引时用本页 items 兜底 refs 查找表。

web/src/lib/mock/handler.ts

@@ -2172,7 +2172,13 @@ function route(m: string, path: string, seg: string[], q: URLSearchParams, b: Re
         if (node) refs[id] = node;
       }
     }
-    return { items, total: matched.length, page, size, edges, refs };
+    // 顺带带上本页节点(含邻居)锚定的资产,供展开时展示。
+    const assets: Record<string, ReturnType<typeof D.nodeAssetsFor>> = {};
+    for (const id of new Set([...onPage, ...Object.keys(refs)])) {
+      const anchored = D.nodeAssetsFor(id);
+      if (anchored.length > 0) assets[id] = anchored;
+    }
+    return { items, total: matched.length, page, size, edges, refs, assets };
   }
   if (path === "/exploration/activity" && seg.length === 2) {
     const since = Number(q.get("since") ?? 0);