feat: 新增表格文件预览，优化知识图谱与 Agent 详情交互

- 新增 spreadsheet-preview 组件及 xlsx 解析工具，支持产物中的表格文件预览
- 优化知识图谱画布、详情面板及样式
- 调整 Agent 详情面板、聊天与消息列表交互

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

frontend-web/src/pages/KnowledgeGraphPage.tsx

@@ -28,10 +28,12 @@ import {
   getNodeTitle,
 } from "@/components/knowledge-graph/graphUtils";
 import "@/components/knowledge-graph/graphStyles.css";
+import { useTheme } from "@/contexts/ThemeContext";
 import { useKnowledgeGraph, useKnowledgeNote } from "@/core/knowledge/hooks";
 
 export default function KnowledgeGraphPage() {
   const navigate = useNavigate();
+  const { theme } = useTheme();
   const pageRef = useRef<HTMLDivElement>(null);
   const canvasRef = useRef<GraphCanvasHandle>(null);
 
@@ -54,7 +56,7 @@ export default function KnowledgeGraphPage() {
   const [showDetail, setShowDetail] = useState(false);
   const [zoomLevel, setZoomLevel] = useState(1);
   const [tooltip, setTooltip] = useState<TooltipState | null>(null);
-  const [graphMode, setGraphMode] = useState<GraphMode>("explore");
+  const [graphMode, setGraphMode] = useState<GraphMode>("full");
   const [exploreRootId, setExploreRootId] = useState<string | null>(null);
   const [expandedNodeIds, setExpandedNodeIds] = useState<Set<string>>(new Set());
   const [visibleNodeIds, setVisibleNodeIds] = useState<Set<string>>(new Set());
@@ -269,14 +271,16 @@ export default function KnowledgeGraphPage() {
     return matches;
   }, [searchKeyword, filteredNodes]);
 
-  const topNodes = useMemo(
-    () =>
-      [...allNodes]
-        .map((node) => ({ node, degree: degrees.get(node.id) ?? 0 }))
-        .sort((a, b) => b.degree - a.degree)
-        .slice(0, 8),
-    [allNodes, degrees],
-  );
+  const topNodes = useMemo(() => {
+    // 搜索时核心节点榜单只保留命中的节点,与画布高亮保持一致。
+    const pool = searchMatchIds
+      ? filteredNodes.filter((node) => searchMatchIds.has(node.id))
+      : allNodes;
+    return pool
+      .map((node) => ({ node, degree: degrees.get(node.id) ?? 0 }))
+      .sort((a, b) => b.degree - a.degree)
+      .slice(0, 8);
+  }, [allNodes, filteredNodes, searchMatchIds, degrees]);
 
   const selectedNode = selectedNodeId ? (nodeById.get(selectedNodeId) ?? null) : null;
   const selectedNeighbors = useMemo(() => {
@@ -633,6 +637,7 @@ export default function KnowledgeGraphPage() {
             searchMatchIds={searchMatchIds}
             layoutType={layoutType}
             showLabels={showLabels}
+            theme={theme}
             onSelectNode={handleSelectNode}
             onTooltip={setTooltip}
             onZoomChange={setZoomLevel}