fix: restore signs after navigation

tests/browser/journey-integration.spec.ts

@@ -163,6 +163,36 @@ test('suppresses roadside signs for explicit navigation and history restoration'
   expect((await readSceneInstrumentation(page)).routeLabelsDrawn).toEqual([]);
 });
 
+test('restores the next sign after a navigator round trip', async ({
+  page,
+  distUrl,
+}) => {
+  await page.goto(distUrl, { waitUntil: 'domcontentloaded' });
+  await expect(page.locator('.journey-world')).toHaveAttribute('data-scene-state', 'running');
+
+  await clickNavigationLink(page, '#profile');
+  await expect(page.locator('#profile-heading')).toBeFocused();
+  await clickNavigationLink(page, '#start');
+  await expect(page.locator('#start-heading')).toBeFocused();
+
+  const destination = await page.evaluate(() => {
+    const profile = document.getElementById('profile-heading');
+    if (!(profile instanceof HTMLElement)) throw new Error('Missing profile heading');
+    const viewportHeight = window.visualViewport?.height ?? window.innerHeight;
+    return Math.max(
+      1,
+      profile.getBoundingClientRect().top + window.scrollY
+        - viewportHeight * (0.35 + 0.45),
+    );
+  });
+  await page.mouse.wheel(0, 1);
+  await page.evaluate((scrollY) => window.scrollTo(0, scrollY), destination);
+
+  await expect.poll(async () => (
+    await readSceneInstrumentation(page)
+  ).signFrames.some((frame) => frame.targetId === 'profile')).toBe(true);
+});
+
 test('reconciles an idle rapid jump to the latest active route without flashing intermediates', async ({
   page,
   distUrl,