feat(frontend): 对齐万华门户风格并更新全量截图文档

- 新增门户导航子页面（交易信息、政策法规、操作指南、常见问题、采购平台）并统一门户壳层样式
- 按万华站点风格重构首页与登录页（导航、轮播、公告、登录区）
- 优化小滨助手：首页/登录页接入、可拖拽吸边、圆形图标、圆形外框与切换动画优化
- 重新生成全量页面截图并更新《滨化智慧招标平台-前端界面截图汇总.docx》

Co-authored-by: Cursor <cursoragent@cursor.com>

front-end/src/app/pages/portal/TradingInfoPage.tsx

@@ -0,0 +1,75 @@
+import { useState } from "react";
+import { cn } from "../../components/ui/utils";
+import { PortalShell } from "./PortalShell";
+
+type Notice = { title: string; date: string };
+
+const NOTICE_TABS = ["招标公告", "资格预审公告", "中标候选人公示", "结果公告", "终止公告"];
+
+const NOTICE_DATA: Record<string, Notice[]> = {
+  招标公告: [
+    { title: "[公开招标] 扣电测试柜框架", date: "2026-07-13" },
+    { title: "[公开招标] 2026年地脚螺栓、不锈钢及五金紧固件框架招标", date: "2026-07-13" },
+    { title: "[公开招标] 万华莱州100MW分散式风电项目EPC工程总承包[变更公告]", date: "2026-07-13" },
+    { title: "[公开招标] TPU掺混特种线项目FFS包装机[变更公告]", date: "2026-07-13" },
+  ],
+  资格预审公告: [
+    { title: "滨州园区危化品运输服务资格预审公告", date: "2026-07-11" },
+    { title: "公辅系统维保服务资格预审公告", date: "2026-07-10" },
+    { title: "智慧园区网络安全服务资格预审公告", date: "2026-07-08" },
+  ],
+  中标候选人公示: [
+    { title: "[公开招标] 牵引车租赁服务框架中标候选人公示", date: "2026-07-07" },
+    { title: "[公开招标] 电池材料项目地质勘察工程中标候选人公示", date: "2026-07-06" },
+    { title: "[公开招标] 四轮防爆巡检机器人系统中标候选人公示", date: "2026-06-26" },
+  ],
+  结果公告: [
+    { title: "[公开招标] HDPE管道管件框架招标中标结果公告", date: "2026-07-07" },
+    { title: "[公开招标] 万华起重框架招标包一 单梁起重机中标结果公告", date: "2026-07-02" },
+    { title: "[公开招标] 万华海阳绿电直连光伏组件项目中标结果公告", date: "2026-06-30" },
+  ],
+  终止公告: [
+    { title: "国标切断双偏心蝶阀框架招标废标公告", date: "2026-07-06" },
+    { title: "TPU四期熟化料仓招标废标公告", date: "2026-07-01" },
+    { title: "万华滨州碳酸锂项目冷却窑废标公告", date: "2026-06-24" },
+  ],
+};
+
+export function TradingInfoPage() {
+  const [activeTab, setActiveTab] = useState(NOTICE_TABS[0]);
+  return (
+    <PortalShell active="trading">
+      <section className="border bg-white">
+        <div className="border-b bg-[#f8fafc] px-4 py-3">
+          <h1 className="text-base font-semibold">交易信息</h1>
+        </div>
+        <div className="border-b px-3">
+          <div className="flex flex-wrap items-center">
+            {NOTICE_TABS.map((tab) => (
+              <button
+                key={tab}
+                onClick={() => setActiveTab(tab)}
+                className={cn(
+                  "relative px-4 py-3 text-sm",
+                  activeTab === tab ? "font-semibold text-primary" : "text-[#4b5563] hover:text-primary",
+                )}
+              >
+                {tab}
+                {activeTab === tab && <span className="absolute inset-x-2 bottom-0 h-0.5 bg-primary" />}
+              </button>
+            ))}
+          </div>
+        </div>
+        <ul className="space-y-1 p-4">
+          {NOTICE_DATA[activeTab].map((n) => (
+            <li key={n.title} className="flex items-center gap-3 border-b border-dashed py-2 text-sm">
+              <span className="line-clamp-1 flex-1 hover:text-primary">{n.title}</span>
+              <span className="text-xs text-muted-foreground">{n.date}</span>
+            </li>
+          ))}
+        </ul>
+      </section>
+    </PortalShell>
+  );
+}
+