fix(ui): 修复价格尾零、增加币种下拉框，并重构持仓引擎实现原币种/本位币双轨制盈亏计算

app/dashboard/assets/page.tsx

@@ -10,6 +10,7 @@ import {
   TableHeader,
   TableRow,
 } from '@/components/ui/table';
+import Big from 'big.js';
 
 export default async function AssetsPage() {
   const assets = await getAssets();
@@ -53,14 +54,14 @@ export default async function AssetsPage() {
                   <TableCell className="font-medium">{asset.symbol}</TableCell>
                   <TableCell>{typeLabels[asset.type] || asset.type}</TableCell>
                   <TableCell>{asset.baseCurrency}</TableCell>
-                  <TableCell>{asset.latestPrice}</TableCell>
+                  <TableCell>{asset.latestPrice ? new Big(asset.latestPrice).toString() : '-'}</TableCell>
                   <TableCell>
                     {asset.createdAt
                       ? new Date(asset.createdAt).toLocaleString('zh-CN')
                       : '-'}
                   </TableCell>
                   <TableCell>
-                    <UpdatePriceDialog assetId={asset.id} currentPrice={asset.latestPrice || '0'} />
+                    <UpdatePriceDialog assetId={asset.id} currentPrice={asset.latestPrice ? new Big(asset.latestPrice).toString() : '0'} />
                   </TableCell>
                 </TableRow>
               ))