activities: use sessionStorage for selected tab

The useLocalStorage hook synchronizes state between windows. In the
case of the activities tabs, we don't want this state synchronized,
otherwise changing a tab in one window would change the tab in all
open windows.

Instead, we can use sessionStorage so that the state persists when
refreshing or duplicating a browser tab. Local storage is still used
as the default value so that any new window that is opened will use
the last selected state.

Issue: https://github.com/pybricks/support/issues/807

src/activities/Activities.test.tsx

@@ -11,6 +11,7 @@ afterEach(() => {
     cleanup();
     jest.resetAllMocks();
     localStorage.clear();
+    sessionStorage.clear();
 });
 
 describe('Activities', () => {

src/activities/hooks.ts

@@ -1,7 +1,8 @@
 // SPDX-License-Identifier: MIT
 // Copyright (c) 2022 The Pybricks Authors
 
-import { useLocalStorage } from 'usehooks-ts';
+import { useEffect } from 'react';
+import { useEffectOnce, useLocalStorage, useSessionStorage } from 'usehooks-ts';
 
 /** Indicates the selected activity. */
 export enum Activity {
@@ -17,6 +18,28 @@ export enum Activity {
  * React hook for getting and setting the selected activity in the activity panel.
  * @returns a tuple of the current state and the setter function (like useState()).
  */
-export function useActivitiesSelectedActivity() {
-    return useLocalStorage('activities.selectedActivity', Activity.Explorer);
+export function useActivitiesSelectedActivity(): ReturnType<
+    typeof useSessionStorage<Activity>
+> {
+    // If multiple windows are open, this allows each window to control the
+    // current activity independently. The local storage uses a "last one wins"
+    // approach to deciding which state to restore when a window is opened.
+    const [lastSelectedActivity, setLastSelectedActivity] = useLocalStorage(
+        'activities.selectedActivity',
+        Activity.Explorer,
+    );
+
+    const [selectedActivity, setSelectedActivity] = useSessionStorage(
+        'activities.selectedActivity',
+        lastSelectedActivity,
+    );
+
+    // Force writing to session storage since default value is not constant.
+    useEffectOnce(() => setSelectedActivity(selectedActivity));
+
+    useEffect(() => {
+        setLastSelectedActivity(selectedActivity);
+    }, [selectedActivity]);
+
+    return [selectedActivity, setSelectedActivity];
 }