fix(ui): stop the 'Video speed' label wrapping in the Output panel

Widen the panel (280->300px), keep control labels on one line (white-space:
nowrap), and let the range shrink (min-width:0) instead of pushing the label
to a second row. +1 e2e (panel-layout.spec.ts).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

simulator/e2e/tests/panel-layout.spec.ts

@@ -0,0 +1,25 @@
+import { test, expect, Page } from "@playwright/test";
+
+// Guard: the "Video speed" control label must stay on ONE line in the Output panel
+// (it was wrapping to two rows at the old panel width).
+
+async function enter(page: Page) {
+  await page.goto("/");
+  await page.waitForFunction(() => (window as any).__hefReady === true, null, { timeout: 45_000 });
+  await page.locator("#welcome-launch").click();
+  await page.waitForSelector("#welcome", { state: "detached", timeout: 10_000 });
+}
+
+test('the "Video speed" label does not wrap to a second line', async ({ page }) => {
+  await enter(page);
+  const info = await page.evaluate(() => {
+    const span = document.querySelector('.panel .play-speed span[data-i18n="speed.label"]') as HTMLElement;
+    const cs = getComputedStyle(span);
+    let lh = parseFloat(cs.lineHeight);
+    if (Number.isNaN(lh)) lh = parseFloat(cs.fontSize) * 1.3; // "normal"
+    return { text: span.textContent, height: span.getBoundingClientRect().height, lineHeight: lh };
+  });
+  expect(info.text).toBe("Video speed");
+  // A wrapped label is ~2× a single line; allow slack but stay well under two lines.
+  expect(info.height).toBeLessThan(info.lineHeight * 1.6);
+});