feat(ui): 引入 sonner 消息反馈系统，并在首页部署全局行情同步按钮

app/dashboard/page.tsx

@@ -2,6 +2,7 @@ import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
 import { getPortfolioSummary } from '@/actions/portfolio';
 import { formatQuantity, formatAmount } from '@/lib/formatters';
 import AllocationChart from '@/components/dashboard/allocation-chart';
+import { SyncButton } from '@/components/assets/sync-button';
 import Big from 'big.js';
 
 const CHART_COLORS = [
@@ -33,6 +34,10 @@ export default async function DashboardPage() {
       </div>
 
       <Card>
+        <CardHeader className="flex flex-row items-center justify-between space-y-0 pb-2">
+          <CardTitle className="text-sm font-medium">总资产概览</CardTitle>
+          <SyncButton />
+        </CardHeader>
         <CardContent className="pt-6 pb-6">
           <div className="flex items-center gap-3">
             <span className="text-2xl font-semibold text-muted-foreground">

app/layout.tsx

@@ -2,6 +2,7 @@ import type { Metadata } from "next";
 import { Geist, Geist_Mono } from "next/font/google";
 import "./globals.css";
 import { ThemeProvider } from "@/components/theme-provider";
+import { Toaster } from "@/components/ui/sonner";
 
 const geistSans = Geist({
   variable: "--font-geist-sans",
@@ -29,6 +30,7 @@ export default function RootLayout({
         <ThemeProvider attribute="class" defaultTheme="system" enableSystem disableTransitionOnChange>
           {children}
         </ThemeProvider>
+        <Toaster />
       </body>
     </html>
   );