chore: prepare local.3 release and test event subscriptions

web/src/lib/utils/__tests__/EventNavigation.svelte

@@ -0,0 +1,17 @@
+<script lang="ts">
+  import { BaseEventManager } from '$lib/utils/base-event-manager.svelte';
+  import EventSubscriber from './EventSubscriber.svelte';
+
+  const manager = new BaseEventManager<{ update: [] }>();
+  let page = $state(0);
+  let visible = $state(true);
+</script>
+
+<button type="button" onclick={() => page++}>Next page</button>
+<button type="button" onclick={() => (visible = !visible)}>Toggle subscriber</button>
+<button type="button" disabled={!manager.hasListeners('update')} onclick={() => manager.emit('update')}>Update</button>
+{#if visible}
+  {#key page}
+    <EventSubscriber {manager} />
+  {/key}
+{/if}

web/src/lib/utils/__tests__/EventSubscriber.svelte

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+<script lang="ts">
+  import { onDestroy } from 'svelte';
+  import type { BaseEventManager } from '$lib/utils/base-event-manager.svelte';
+
+  const { manager }: { manager: BaseEventManager<{ update: [] }> } = $props();
+  let received = $state(0);
+  onDestroy(manager.on({ update: () => received++ }));
+</script>
+
+<span data-testid="received">{received}</span>

web/src/lib/utils/base-event-manager.spec.ts

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+import { render, screen } from '@testing-library/svelte';
+import userEvent from '@testing-library/user-event';
+import EventNavigation from './__tests__/EventNavigation.svelte';
+
+describe('event subscriptions across navigation', () => {
+  it('keeps the new page subscribed when the previous page is destroyed', async () => {
+    const user = userEvent.setup();
+    render(EventNavigation);
+    for (let page = 0; page < 3; page++) {
+      await user.click(screen.getByRole('button', { name: 'Next page' }));
+      await user.click(screen.getByRole('button', { name: 'Update' }));
+      expect(screen.getByTestId('received')).toHaveTextContent('1');
+    }
+  });
+
+  it('updates controls when the last subscriber is removed and restored', async () => {
+    const user = userEvent.setup();
+    render(EventNavigation);
+    const update = screen.getByRole('button', { name: 'Update' });
+    expect(update).toBeEnabled();
+    await user.click(screen.getByRole('button', { name: 'Toggle subscriber' }));
+    expect(update).toBeDisabled();
+    await user.click(screen.getByRole('button', { name: 'Toggle subscriber' }));
+    expect(update).toBeEnabled();
+    await user.click(update);
+    expect(screen.getByTestId('received')).toHaveTextContent('1');
+  });
+});