perf(app): limit initial sidebar workspace rendering

Large project, status, and pinned groups now render 20 rows until expanded. Newly discovered workspaces are prepended without disturbing the saved order.

packages/app/src/hooks/sidebar-workspaces-view-model.ts

@@ -477,6 +477,23 @@ export function appendMissingOrderKeys(input: {
   return [...input.currentOrder, ...missingKeys];
 }
 
+export function prependMissingOrderKeys(input: {
+  currentOrder: string[];
+  visibleKeys: string[];
+}): string[] {
+  if (input.visibleKeys.length === 0) {
+    return input.currentOrder;
+  }
+
+  const existingKeys = new Set(input.currentOrder);
+  const missingKeys = input.visibleKeys.filter((key) => !existingKeys.has(key));
+  if (missingKeys.length === 0) {
+    return input.currentOrder;
+  }
+
+  return [...missingKeys, ...input.currentOrder];
+}
+
 export interface SidebarOrderUpdates {
   projectOrder: string[] | null;
   workspaceOrders: Array<{ projectKey: string; order: string[] }>;
@@ -500,7 +517,7 @@ export function computeSidebarOrderUpdates(input: {
   const workspaceOrders: Array<{ projectKey: string; order: string[] }> = [];
   for (const project of input.projects) {
     const persistedWorkspaceOrder = input.getWorkspaceOrder(project.projectKey);
-    const nextWorkspaceOrder = appendMissingOrderKeys({
+    const nextWorkspaceOrder = prependMissingOrderKeys({
       currentOrder: persistedWorkspaceOrder,
       visibleKeys: project.workspaces.map((workspace) => workspace.workspaceKey),
     });