fix: preserve model selection when toggling series

client/src/components/VehicleTree.tsx

@@ -171,10 +171,7 @@ export default function VehicleTree({ selection, onSelect }: Props) {
             <div
               className={`flex items-center gap-1 px-1 py-1 rounded cursor-pointer group text-xs
                 ${isSeriesSelected ? 'bg-primary/20 text-primary' : 'hover:bg-secondary/60'}`}
-              onClick={() => {
-                toggleSeries(series.id);
-                onSelect({ seriesId: series.id, modelId: null, taskId: null });
-              }}
+              onClick={() => toggleSeries(series.id)}
             >
               {expanded ? <ChevronDown className="w-3 h-3 flex-shrink-0 text-muted-foreground" /> : <ChevronRight className="w-3 h-3 flex-shrink-0 text-muted-foreground" />}
               <Train className="w-3 h-3 flex-shrink-0 text-muted-foreground" />

client/src/pages/Home.tsx

@@ -278,14 +278,11 @@ export default function Home() {
 
   // ── 左侧面板渲染 ───────────────────────────────────────────────────────────
   const renderLeftPanel = () => {
-    if (selection.modelId == null) {
-      return (
-        <VehicleTree selection={selection} onSelect={setSelection} />
-      );
-    }
     return (
       <div className="flex min-h-0 flex-1 flex-col">
         <VehicleTree selection={selection} onSelect={setSelection} />
+        {selection.modelId != null && (
+          <>
             <div className="h-px bg-border my-1" />
             <TaskManager
               modelId={selection.modelId}
@@ -296,6 +293,8 @@ export default function Home() {
               onCadFilesSelectionChange={setSelectedTaskCadFileIds}
               onSelectTaskCad={handleSelectCad}
             />
+          </>
+        )}
       </div>
     );
   };