fix: keep Windows header menu aligned

Moved the Windows app menu into the fixed titlebar controls
Kept sidebar controls stable when opening and closing the sidebar
Documented longer validation timeouts for workspace checks

AGENTS.md

@@ -451,7 +451,7 @@ A single store with N properties means every subscriber re-evaluates on every st
 
 ## Validation expectations
 
-- Run `bun run type-check` and `bun run lint` before finalizing source-code changes that can affect TypeScript, runtime behavior, builds, lint rules, package resolution, or generated assets. For docs-only or isolated config-only changes, run the narrowest relevant validation instead (for example JSON/schema validation) and do not run the full checks unless the change can affect code execution.
+- Run `bun run type-check` and `bun run lint` before finalizing source-code changes that can affect TypeScript, runtime behavior, builds, lint rules, package resolution, or generated assets. Use a sufficiently long tool timeout for these workspace-wide checks (for example 240000ms) so successful package-level results are not lost to a tool timeout. For docs-only or isolated config-only changes, run the narrowest relevant validation instead (for example JSON/schema validation) and do not run the full checks unless the change can affect code execution.
 - For hot-path changes, verify behavior under streaming or repeated events, not just static render.
 - For sync or startup changes, verify fresh load, retry/failure, and restart behavior.
 - For session changes, verify create, stream, abort, permission, archive/delete, and revisit flows when relevant.

packages/ui/src/components/layout/Header.tsx

@@ -1417,16 +1417,6 @@ export const Header: React.FC<HeaderProps> = ({
     toggleSidebar();
   }, [blurActiveElement, isMobile, isSessionSwitcherOpen, setSessionSwitcherOpen, toggleSidebar]);
 
-  const handleOpenWindowsAppMenu = React.useCallback((event: React.MouseEvent<HTMLButtonElement>) => {
-    const rect = event.currentTarget.getBoundingClientRect();
-    void invokeDesktop('desktop_show_app_menu', {
-      x: rect.left,
-      y: rect.bottom,
-    }).catch((error) => {
-      console.warn('[header] failed to open app menu', error);
-    });
-  }, []);
-
   const handleOpenDraftMiniChat = React.useCallback(() => {
     void invokeDesktop('desktop_open_draft_mini_chat_window', {
       directory: normalize(openDirectory || activeProject?.path || ''),
@@ -2154,15 +2144,6 @@ export const Header: React.FC<HeaderProps> = ({
         className="app-region-no-drag shrink-0 self-stretch transition-[width] duration-200 ease-[cubic-bezier(0.22,1,0.36,1)] motion-reduce:transition-none"
         style={{ width: headerControlsSpacerWidth }}
       />
-      {isWindowsElectronDesktop ? (
-        <HeaderIconActionButton
-          title={t('header.actions.openAppMenu')}
-          ariaLabel={t('header.actions.openAppMenuAria')}
-          onClick={handleOpenWindowsAppMenu}
-          className={`${desktopHeaderIconButtonClass} shrink-0`}
-          Icon={'menu-2'}
-        />
-      ) : null}
       {/* Sidebar toggle + project actions live in the persistent
           TitlebarLeftControls overlay; the header reserves matching left space
           via padding (see headerStyle) when the sidebar is collapsed. */}

packages/ui/src/components/layout/TitlebarLeftControls.tsx

@@ -7,6 +7,7 @@ import { useI18n } from '@/lib/i18n';
 import { useProjectActionsContext } from '@/hooks/useProjectActionsContext';
 import { ProjectActionsButton } from '@/components/layout/ProjectActionsButton';
 import { formatShortcutForDisplay, getEffectiveShortcutCombo } from '@/lib/shortcuts';
+import { invokeDesktop } from '@/lib/desktop';
 
 const ICON_BUTTON_CLASS =
   'app-region-no-drag inline-flex h-8 w-8 items-center justify-center gap-2 rounded-md typography-ui-label font-medium text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary hover:bg-interactive-hover transition-colors';
@@ -31,6 +32,22 @@ export const TitlebarLeftControls: React.FC = () => {
   const clusterRef = React.useRef<HTMLDivElement | null>(null);
 
   const toggleShortcut = formatShortcutForDisplay(getEffectiveShortcutCombo('toggle_sidebar', shortcutOverrides));
+  const isWindowsElectronDesktop = React.useMemo(() => {
+    if (typeof window === 'undefined') {
+      return false;
+    }
+    return Boolean(window.__OPENCHAMBER_ELECTRON__) && window.__OPENCHAMBER_PLATFORM__ === 'win32';
+  }, []);
+
+  const handleOpenWindowsAppMenu = React.useCallback((event: React.MouseEvent<HTMLButtonElement>) => {
+    const rect = event.currentTarget.getBoundingClientRect();
+    void invokeDesktop('desktop_show_app_menu', {
+      x: rect.left,
+      y: rect.bottom,
+    }).catch((error) => {
+      console.warn('[titlebar] failed to open app menu', error);
+    });
+  }, []);
 
   React.useEffect(() => {
     if (typeof document === 'undefined') {
@@ -71,6 +88,24 @@ export const TitlebarLeftControls: React.FC = () => {
       }}
     >
       <div ref={clusterRef} className="flex items-center gap-2">
+        {isWindowsElectronDesktop ? (
+          <Tooltip>
+            <TooltipTrigger asChild>
+              <button
+                type="button"
+                onClick={handleOpenWindowsAppMenu}
+                aria-label={t('header.actions.openAppMenuAria')}
+                className={cn(ICON_BUTTON_CLASS, 'shrink-0')}
+              >
+                <Icon name="menu-2" className="h-[18px] w-[18px]" />
+              </button>
+            </TooltipTrigger>
+            <TooltipContent>
+              <p>{t('header.actions.openAppMenu')}</p>
+            </TooltipContent>
+          </Tooltip>
+        ) : null}
+
         <Tooltip>
           <TooltipTrigger asChild>
             <button