feat: login form as a client component, theme toggle

jest.setup.cjs

@@ -0,0 +1,27 @@
+require('@testing-library/jest-dom');
+
+const { getComputedStyle } = window;
+window.getComputedStyle = (elt) => getComputedStyle(elt);
+window.HTMLElement.prototype.scrollIntoView = () => {};
+
+Object.defineProperty(window, 'matchMedia', {
+  writable: true,
+  value: jest.fn().mockImplementation((query) => ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addListener: jest.fn(),
+    removeListener: jest.fn(),
+    addEventListener: jest.fn(),
+    removeEventListener: jest.fn(),
+    dispatchEvent: jest.fn(),
+  })),
+});
+
+class ResizeObserver {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+}
+
+window.ResizeObserver = ResizeObserver;