fix(webui): preserve route position when tabs activate

webui/src/lib/components/SegmentedNav.svelte

@@ -19,9 +19,15 @@
   $effect(() => {
     active;
     if (typeof document === "undefined") return;
-    queueMicrotask(() => tablist
-      ?.querySelector<HTMLElement>('[aria-selected="true"]')
-      ?.scrollIntoView({ block: "nearest", inline: "nearest" }));
+    queueMicrotask(() => {
+      const selected = tablist?.querySelector<HTMLElement>('[aria-selected="true"]');
+      if (!tablist || !selected) return;
+      const start = selected.offsetLeft;
+      const end = start + selected.offsetWidth;
+      if (start < tablist.scrollLeft) tablist.scrollTo({ left: start });
+      else if (end > tablist.scrollLeft + tablist.clientWidth)
+        tablist.scrollTo({ left: end - tablist.clientWidth });
+    });
   });
 
   function navigate(event: KeyboardEvent) {

webui/tests/parity.e2e.ts

@@ -745,7 +745,16 @@ for (const viewport of viewports) {
         }
         await mockApi(page);
         await page.goto(route);
-        await expect(page.getByRole("heading", { name: heading, level: 1 })).toBeVisible();
+        const pageHeading = page.getByRole("heading", { name: heading, level: 1 });
+        await expect(pageHeading).toBeVisible();
+        if (route === "#/integrations/extensions") {
+          await expect(page.getByText("Extension manager", { exact: true })).toBeVisible();
+        }
+        await page.evaluate(() => new Promise<void>((resolve) =>
+          requestAnimationFrame(() => requestAnimationFrame(() => resolve())),
+        ));
+        expect(await page.evaluate(() => window.scrollY)).toBe(0);
+        expect((await pageHeading.boundingBox())?.y).toBeGreaterThanOrEqual(0);
         await expect.poll(() => page.evaluate(() =>
           document.documentElement.scrollWidth <= document.documentElement.clientWidth)).toBe(true);
         if (route === "#/activity") {