fix: add getAnimations polyfill to global test setup and mock hardwareConcurrency

- test/setup.ts: stub Element.getAnimations for @base-ui ScrollAreaViewport
  (7 unhandled errors causing vitest to exit non-zero despite 2696 tests passing)
- observatory-world-canvas.performance.test: mock navigator.hardwareConcurrency=8
  for consistent behavior across local (high-core) and CI (2-core) environments

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: bb-connor

apps/workbench/src/test/setup.ts

@@ -4,6 +4,13 @@ import { beforeEach } from "vitest";
 // jsdom does not implement ResizeObserver. Provide a minimal stub so
 // components that rely on it (e.g. PaneTabBar overflow detection) don't
 // throw and trip the ErrorBoundary during tests.
+// jsdom does not implement Element.getAnimations (Web Animations API).
+// @base-ui/react ScrollAreaViewport calls it on a deferred timer, causing
+// unhandled exceptions that make vitest exit non-zero despite all tests passing.
+if (typeof Element.prototype.getAnimations === "undefined") {
+  Element.prototype.getAnimations = () => [];
+}
+
 if (typeof globalThis.ResizeObserver === "undefined") {
   globalThis.ResizeObserver = class ResizeObserver {
     observe() {}