🤖 fix(chromatic): hide manual toggle when running in Chromatic UI tests

Author: ammar-agent

.storybook/preview.tsx

@@ -3,6 +3,13 @@ import type { Preview } from "@storybook/react-vite";
 import { ThemeProvider, type ThemeMode } from "../src/browser/contexts/ThemeContext";
 import { getStorageChangeEvent } from "@/common/constants/events";
 import { UI_THEME_KEY } from "@/common/constants/storage";
+
+// Utility: detect e2e/test contexts where UI should be hidden (Chromatic, SB test-runner)
+const isE2ETestEnv = () => {
+  if (typeof window !== "undefined" && (window as any).CHROMATIC) return true;
+  if (typeof navigator !== "undefined" && /StorybookTestRunner/i.test(navigator.userAgent)) return true;
+  return false;
+};
 import "../src/browser/styles/globals.css";
 
 const applyStorybookTheme = (mode: ThemeMode) => {
@@ -101,7 +108,7 @@ const preview: Preview = {
       return (
         <ThemeProvider>
           <Story />
-          {!mode && (typeof navigator === "undefined" || !/StorybookTestRunner/i.test(navigator.userAgent)) && (
+          {!mode && !isE2ETestEnv() && (
             <StorybookThemeToggle initialTheme={resolved} />
           )}
         </ThemeProvider>