feat: add core UI components and baseline tests

packages/ui/src/test/setup.ts

@@ -0,0 +1,64 @@
+import "@testing-library/jest-dom/vitest";
+
+import { cleanup } from "@testing-library/react";
+import { afterEach, vi } from "vitest";
+
+afterEach(() => {
+  cleanup();
+});
+
+class ResizeObserverMock {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+}
+
+class PointerEventMock extends MouseEvent {
+  constructor(type: string, props: PointerEventInit = {}) {
+    super(type, props);
+  }
+}
+
+Object.defineProperty(window, "matchMedia", {
+  writable: true,
+  value: vi.fn().mockImplementation((query: string) => ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addEventListener: vi.fn(),
+    removeEventListener: vi.fn(),
+    addListener: vi.fn(),
+    removeListener: vi.fn(),
+    dispatchEvent: vi.fn()
+  }))
+});
+
+Object.defineProperty(window, "ResizeObserver", {
+  writable: true,
+  value: ResizeObserverMock
+});
+
+Object.defineProperty(window, "PointerEvent", {
+  writable: true,
+  value: PointerEventMock
+});
+
+Object.defineProperty(window.HTMLElement.prototype, "scrollIntoView", {
+  configurable: true,
+  value: vi.fn()
+});
+
+Object.defineProperty(window.HTMLElement.prototype, "hasPointerCapture", {
+  configurable: true,
+  value: vi.fn(() => false)
+});
+
+Object.defineProperty(window.HTMLElement.prototype, "releasePointerCapture", {
+  configurable: true,
+  value: vi.fn()
+});
+
+Object.defineProperty(window.HTMLElement.prototype, "setPointerCapture", {
+  configurable: true,
+  value: vi.fn()
+});