feat(app): retain workspace screens on sidebar switch

packages/app/src/hooks/use-workspace-navigation.ts

@@ -1,17 +1,27 @@
 import { useCallback } from "react";
 import { router } from "expo-router";
+import {
+  activateNavigationWorkspaceSelection,
+  getNavigationActiveWorkspaceSelection,
+} from "@/stores/navigation-active-workspace-store";
 import { buildHostWorkspaceRoute } from "@/utils/host-routes";
 
 /**
- * Navigate to a workspace screen. Uses router.navigate() which,
- * combined with getId on the workspace Stack.Screen, ensures:
- * - Only one instance of each workspace exists in the stack
- * - History is preserved (back button works)
- * - No duplicate workspace screens
+ * Open a workspace. Once the workspace shell is mounted, switching workspaces
+ * is app-level state so native-stack does not rebuild every retained screen.
  */
 export function navigateToWorkspace(serverId: string, workspaceId: string) {
+  const activeWorkspace = getNavigationActiveWorkspaceSelection();
+  if (activeWorkspace) {
+    activateNavigationWorkspaceSelection(
+      { serverId, workspaceId },
+      { updateBrowserHistory: true, historyMode: "push" },
+    );
+    return;
+  }
+
   const href = buildHostWorkspaceRoute(serverId, workspaceId);
-  router.navigate(href);
+  router.navigate(href as any);
 }
 
 export function useWorkspaceNavigation() {