feat(platform): keep canonical source summary slots

vehicle-data-platform/apps/web/src/pages/Dashboard.tsx

@@ -44,6 +44,13 @@ function formatCount(value?: number | null) {
   return value == null ? '0' : value.toLocaleString();
 }
 
+function formatProtocolRate(row: ProtocolStat) {
+  if (!Number.isFinite(row.total) || row.total <= 0) {
+    return '0%';
+  }
+  return `${Math.round((row.online / row.total) * 100)}%`;
+}
+
 function rowServiceStatus(row: { serviceStatus?: { title: string; severity: string }; onlineSourceCount: number; sourceCount: number }) {
   if (row.serviceStatus) {
     return {
@@ -201,7 +208,7 @@ export function Dashboard({ onOpenVehicle, onOpenQuality, onOpenVehicles }: { on
                   { title: '总数', dataIndex: 'total' },
                   {
                     title: '在线率',
-                    render: (_: unknown, row: ProtocolStat) => `${Math.round((row.online / row.total) * 100)}%`
+                    render: (_: unknown, row: ProtocolStat) => formatProtocolRate(row)
                   },
                   {
                     title: '缺失车辆',