feat(desktop): enable macOS version awareness for UI adjustments

- Fetch macOS major version from Rust to determine layout
- Adjust header padding and height for macOS versions

packages/ui/src/components/chat/ChatMessage.tsx

@@ -755,16 +755,20 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
         onContentChange?.('structural');
     }, [isUser, onContentChange]);
 
+    const setImagePreviewOpen = useUIStore((state) => state.setImagePreviewOpen);
+
     const handleShowPopup = React.useCallback((content: ToolPopupContent) => {
 
         if (content.image) {
             setPopupContent(content);
+            setImagePreviewOpen(true);
         }
-    }, []);
+    }, [setImagePreviewOpen]);
 
     const handlePopupChange = React.useCallback((open: boolean) => {
         setPopupContent((prev) => ({ ...prev, open }));
-    }, []);
+        setImagePreviewOpen(open);
+    }, [setImagePreviewOpen]);
 
     const isAnimationSettled = Boolean(getMessageInfoProp(message.info, 'animationSettled'));
     const isStreamingPhase = streamPhase === 'streaming';

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

@@ -108,15 +108,28 @@ export const Header: React.FC = () => {
   }, []);
 
   const macosMajorVersion = React.useMemo(() => {
+    if (typeof window === 'undefined') {
+      return null;
+    }
+    // Use Tauri-provided version if available (accurate), otherwise fall back to UA parsing
+    const desktopApi = (window as typeof window & { opencodeDesktop?: { macosMajorVersion?: number | null } }).opencodeDesktop;
+    if (desktopApi?.macosMajorVersion != null) {
+      return desktopApi.macosMajorVersion;
+    }
+    // Fallback: WebKit reports "Mac OS X 10_15_7" format where 10 is legacy prefix
     if (typeof navigator === 'undefined') {
       return null;
     }
-    const match = (navigator.userAgent || '').match(/Mac OS X (\d+)[._]/);
+    const match = (navigator.userAgent || '').match(/Mac OS X (\d+)[._](\d+)/);
     if (!match) {
       return null;
     }
-    const parsed = Number.parseInt(match[1], 10);
-    return Number.isNaN(parsed) ? null : parsed;
+    const first = Number.parseInt(match[1], 10);
+    const second = Number.parseInt(match[2], 10);
+    if (Number.isNaN(first)) {
+      return null;
+    }
+    return first === 10 ? second : first;
   }, []);
 
   useEffect(() => {
@@ -296,19 +309,22 @@ export const Header: React.FC = () => {
   const desktopPaddingClass = React.useMemo(() => {
     if (isDesktopApp && isMacPlatform) {
       // Always reserve space for Mac traffic lights since header is always on top
-      return 'pl-[5.125rem]';
+      return 'pl-[5.5rem]';
     }
     return 'pl-3';
   }, [isDesktopApp, isMacPlatform]);
 
   const macosHeaderSizeClass = React.useMemo(() => {
-    if (!isDesktopApp || !isMacPlatform) {
+    if (!isDesktopApp || !isMacPlatform || macosMajorVersion === null) {
       return '';
     }
-    if (macosMajorVersion === null || macosMajorVersion > 15) {
-      return '';
+    if (macosMajorVersion >= 26) {
+      return 'h-12';
     }
-    return 'h-14';
+    if (macosMajorVersion <= 15) {
+      return 'h-14';
+    }
+    return '';
   }, [isDesktopApp, isMacPlatform, macosMajorVersion]);
 
   const updateHeaderHeight = React.useCallback(() => {
@@ -351,7 +367,7 @@ export const Header: React.FC = () => {
 
   useEffect(() => {
     updateHeaderHeight();
-  }, [updateHeaderHeight, isMobile]);
+  }, [updateHeaderHeight, isMobile, macosHeaderSizeClass]);
 
   const handleDragStart = React.useCallback(async (e: React.MouseEvent) => {
     if ((e.target as HTMLElement).closest('button, a, input, select, textarea')) {

packages/ui/src/components/multirun/MultiRunLauncher.tsx

@@ -116,7 +116,7 @@ export const MultiRunLauncher: React.FC<MultiRunLauncherProps> = ({
   const desktopHeaderPaddingClass = React.useMemo(() => {
     if (isDesktopApp && isMacPlatform) {
       // Match main app header: reserve space for Mac traffic lights.
-      return 'pl-[5.125rem]';
+      return 'pl-[5.5rem]';
     }
     return 'pl-3';
   }, [isDesktopApp, isMacPlatform]);
@@ -139,6 +139,20 @@ export const MultiRunLauncher: React.FC<MultiRunLauncherProps> = ({
     }
   }, [isDesktopApp]);
 
+  // Handle ESC key to dismiss
+  React.useEffect(() => {
+    if (!onCancel) return;
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') {
+        e.preventDefault();
+        e.stopPropagation();
+        onCancel();
+      }
+    };
+    window.addEventListener('keydown', handleKeyDown, true);
+    return () => window.removeEventListener('keydown', handleKeyDown, true);
+  }, [onCancel]);
+
   // Use the BranchSelector hook for branch state management
   const [worktreeBaseBranch, setWorktreeBaseBranch] = React.useState<string>('HEAD');
   const { isLoading: isLoadingWorktreeBaseBranches, isGitRepository } = useBranchOptions(currentDirectory);
@@ -306,31 +320,27 @@ export const MultiRunLauncher: React.FC<MultiRunLauncherProps> = ({
       <header
         onMouseDown={handleDragStart}
         className={cn(
-          'flex h-12 items-center justify-between border-b app-region-drag select-none',
+          'relative flex h-12 items-center justify-center border-b app-region-drag select-none',
           desktopHeaderPaddingClass
         )}
         style={{ borderColor: 'var(--interactive-border)' }}
       >
-        <div
-          className="flex items-center gap-3"
-        >
-          <h1 className="typography-ui-label font-medium">New Multi-Run</h1>
-        </div>
+        <h1 className="typography-ui-label font-medium">New Multi-Run</h1>
         {onCancel && (
-          <div className="flex items-center pr-3">
+          <div className="absolute right-0 flex items-center pr-3">
             <Tooltip delayDuration={500}>
               <TooltipTrigger asChild>
                 <button
                   type="button"
                   onClick={onCancel}
-                  aria-label="Close"
+                  aria-label="Close (Esc)"
                   className="inline-flex h-9 w-9 items-center justify-center p-2 text-muted-foreground hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary app-region-no-drag"
                 >
                   <RiCloseLine className="h-5 w-5" />
                 </button>
               </TooltipTrigger>
               <TooltipContent>
-                <p>Close</p>
+                <p>Close (Esc)</p>
               </TooltipContent>
             </Tooltip>
           </div>