feat(圆桌): 大屏多页席位多样式+新窗口React页+布局优化+切历史记录刷新

- 新窗口打开改为渲染应用内 React 大屏（独立全屏路由 /roundtable-dashboard，
  经 localStorage 传数据，无侧边栏），替代原自包含 HTML blob
- 总览页布局：上半两列(总控共识+竞争力排行)，核心风险分布下移到数据研判中心后
- 席位交付/执行路线网格列数自适应(grid.ts)：不足4个卡片撑满整行
- 席位专页主体多样式变体(SeatShowcase)：框架矩阵/洞察卡阵/双栏对比/清单核对/
  发布声明，按席位序号轮转分配，总结席位固定发布声明，全部数据驱动
- 修复切换历史记录时大屏/报告不刷新：渲染期复位入口闸门+hydrate依赖草稿id，
  hydrateSaved清残留data；数据切换时大屏自动回总览页

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

frontend-web/src/roundtable-planning/components/Step3DashboardMode.tsx

@@ -39,6 +39,7 @@ import type { ModelOption } from "@/roundtable-planning/components/Step3ReportMo
 import { ScrollToBottomButton } from "@/roundtable-planning/components/ScrollToBottomButton";
 import { Step2Message } from "@/roundtable-planning/components/Step2Panel";
 import { Step2SandboxLayout } from "@/roundtable-planning/components/Step2SandboxLayout";
+import { DASHBOARD_VIEW_STORAGE_PREFIX } from "@/roundtable-planning/pages/DashboardStandalonePage";
 import { useAutoScroll } from "@/roundtable-planning/hooks/useAutoScroll";
 import { useDialogueSpeedMetrics } from "@/roundtable-planning/hooks/useDialogueSpeedMetrics";
 import type { UseStep3DashboardReturn } from "@/roundtable-planning/hooks/useStep3Dashboard";
@@ -113,13 +114,25 @@ export function Step3DashboardMode({
     return () => setPreviewEnabled(false);
   }, [view, setPreviewEnabled]);
 
-  // 新窗口打开：把自包含 HTML 大屏（renderDashboardHtml 产物）在新标签页打开。
+  // 新窗口打开：把当前大屏数据写进 localStorage，在新标签页打开应用内 React 大屏
+  // （独立全屏路由 /roundtable-dashboard，无侧边栏）。无真实数据时 standalone 回落 DEMO。
   const handleOpenNewWindow = () => {
-    if (!html || typeof window === "undefined") return;
-    const blob = new Blob([html], { type: "text/html;charset=utf-8" });
-    const url = URL.createObjectURL(blob);
+    if (typeof window === "undefined") return;
+    const key = `${DASHBOARD_VIEW_STORAGE_PREFIX}${Date.now()}`;
+    try {
+      // 先清掉历史键，避免 localStorage 堆积；再写本次数据。
+      for (let i = window.localStorage.length - 1; i >= 0; i -= 1) {
+        const k = window.localStorage.key(i);
+        if (k && k.startsWith(DASHBOARD_VIEW_STORAGE_PREFIX)) window.localStorage.removeItem(k);
+      }
+      if (dashboardData) window.localStorage.setItem(key, JSON.stringify(dashboardData));
+    } catch {
+      // localStorage 不可用（隐私模式/超额）：忽略，新窗口将回落 DEMO 数据。
+    }
+    // HashRouter：在当前页基址上拼 hash 路由，带上数据键。
+    const base = `${window.location.origin}${window.location.pathname}`;
+    const url = `${base}#/roundtable-dashboard?k=${encodeURIComponent(key)}`;
     window.open(url, "_blank", "noopener,noreferrer");
-    window.setTimeout(() => URL.revokeObjectURL(url), 60_000);
   };
 
   const handleRedraw = () => {
@@ -159,9 +172,8 @@ export function Step3DashboardMode({
               <button
                 type="button"
                 onClick={handleOpenNewWindow}
-                disabled={!html}
-                title={html ? "在新标签页打开自包含 HTML 大屏" : "暂无可打开的大屏"}
-                className="bg-white border border-slate-200 text-slate-700 hover:bg-slate-50 disabled:opacity-50 disabled:cursor-not-allowed text-[10.5px] font-bold px-3 py-1.5 rounded-xl flex items-center gap-1 transition"
+                title="在新标签页打开 React 大屏页面（全屏，无侧边栏）"
+                className="bg-white border border-slate-200 text-slate-700 hover:bg-slate-50 text-[10.5px] font-bold px-3 py-1.5 rounded-xl flex items-center gap-1 transition"
               >
                 <ExternalLink className="w-3.5 h-3.5 text-slate-500" />
                 新窗口打开