fix(web): hide the browser preview button on the web build

apps/web/src/components/ChatView.tsx

@@ -2706,8 +2706,10 @@ export default function ChatView(props: ChatViewProps) {
   const splitChatFraction = useBrowserPanelStore((store) => store.splitChatFraction);
   const setSplitChatFraction = useBrowserPanelStore((store) => store.setSplitChatFraction);
   const browserExpanded = useBrowserPanelStore((store) => store.expanded);
+  // The preview is a Chromium webview, which only the desktop app can host: a
+  // web build has no browser to toggle, so it gets no button and no panel.
   // General chats have no project and therefore no dev server to look at.
-  const browserAvailable = !isGeneralChatThread;
+  const browserAvailable = isElectron && !isGeneralChatThread;
   const browserOpen = browserAvailable && browserPanelState.open;
 
   const handleToggleBrowser = useCallback(() => {
@@ -6982,7 +6984,10 @@ export default function ChatView(props: ChatViewProps) {
         {/* The agent's end of the browser is mounted with the thread, not with
             the panel: a closed panel is a closed panel, not the absence of a
             browser, and a request for the browser opens it. */}
-        {browserAvailable && routeThreadRef !== null ? (
+        {!isGeneralChatThread && routeThreadRef !== null ? (
+          // Mounted on the web build too: the host reads the desktop bridge at
+          // effect time and refuses to connect without one, so it costs nothing
+          // there and keeps working if the preload attaches late.
           // The project is passed alongside the thread because a local draft
           // thread has no shell to look it up from, and browser approvals are
           // recorded per project.

apps/web/src/components/settings/SettingsPanels.browser.tsx

@@ -1884,9 +1884,18 @@ describe("GeneralSettingsPanel observability", () => {
 
     await expect.element(page.getByText(/Credential configured · Claude Max/)).toBeInTheDocument();
     await page.getByLabelText("Toggle Claude details").click();
-    await expect.element(page.getByText("Chat configured")).toBeInTheDocument();
-    await expect.element(page.getByText("Usage verified")).toBeInTheDocument();
-    await page.getByText("Advanced: headless chat token").click();
+    await expect.element(page.getByText("Chat configured")).toBeVisible();
+    await expect.element(page.getByText("Usage verified")).toBeVisible();
+    const advancedTokenLabel = page.getByText("Advanced: headless chat token");
+    await expect.element(advancedTokenLabel).toBeVisible();
+    const advancedTokenToggle = advancedTokenLabel.element().closest("summary");
+    // The summary can have stable bounds while its parent is still revealing it.
+    // Wait for that height transition before sending a pointer click.
+    const detailsPanel = advancedTokenToggle?.closest('[data-slot="collapsible-panel"]');
+    if (!advancedTokenToggle || !detailsPanel)
+      throw new Error("Claude details panel did not render");
+    await Promise.all(detailsPanel.getAnimations().map((animation) => animation.finished));
+    await page.elementLocator(advancedTokenToggle).click();
     await expect.element(page.getByText(/Optional for remote or headless chat/)).toBeVisible();
   });