feat: enhance sidebar functionality for mobile and compact views

- Introduced a floating toggle button for mobile to show/hide the sidebar when collapsed.
- Updated sidebar behavior to completely hide on mobile when the new mobileSidebarHidden state is true.
- Added logic to conditionally render sidebar components based on screen size using the new useIsCompact hook.
- Enhanced SidebarHeader to include close and expand buttons for mobile views.
- Refactored CollapseToggleButton to hide in compact mode.
- Implemented HeaderActionsPanel for mobile actions in various views, improving accessibility and usability on smaller screens.

These changes improve the user experience on mobile devices by providing better navigation options and visibility controls.

apps/ui/src/components/layout/sidebar/components/collapse-toggle-button.tsx

@@ -1,6 +1,7 @@
 import { PanelLeft, PanelLeftClose } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { formatShortcut } from '@/store/app-store';
+import { useIsCompact } from '@/hooks/use-media-query';
 
 interface CollapseToggleButtonProps {
   sidebarOpen: boolean;
@@ -13,6 +14,13 @@ export function CollapseToggleButton({
   toggleSidebar,
   shortcut,
 }: CollapseToggleButtonProps) {
+  const isCompact = useIsCompact();
+
+  // Hide when in compact mode (mobile menu is shown in board header)
+  if (isCompact) {
+    return null;
+  }
+
   return (
     <button
       onClick={toggleSidebar}

apps/ui/src/components/layout/sidebar/components/index.ts

@@ -8,3 +8,4 @@ export { ProjectActions } from './project-actions';
 export { SidebarNavigation } from './sidebar-navigation';
 export { ProjectSelectorWithOptions } from './project-selector-with-options';
 export { SidebarFooter } from './sidebar-footer';
+export { MobileSidebarToggle } from './mobile-sidebar-toggle';

apps/ui/src/components/layout/sidebar/components/mobile-sidebar-toggle.tsx

@@ -0,0 +1,42 @@
+import { PanelLeft } from 'lucide-react';
+import { cn } from '@/lib/utils';
+import { useAppStore } from '@/store/app-store';
+import { useIsCompact } from '@/hooks/use-media-query';
+
+/**
+ * Floating toggle button for mobile that completely hides/shows the sidebar.
+ * Positioned at the left-center of the screen.
+ * Only visible on compact/mobile screens when the sidebar is hidden.
+ */
+export function MobileSidebarToggle() {
+  const isCompact = useIsCompact();
+  const { mobileSidebarHidden, toggleMobileSidebarHidden } = useAppStore();
+
+  // Only show on compact screens when sidebar is hidden
+  if (!isCompact || !mobileSidebarHidden) {
+    return null;
+  }
+
+  return (
+    <button
+      onClick={toggleMobileSidebarHidden}
+      className={cn(
+        'fixed left-0 top-1/2 -translate-y-1/2 z-50',
+        'flex items-center justify-center',
+        'w-8 h-12 rounded-r-lg',
+        // Glass morphism background
+        'bg-card/95 backdrop-blur-sm border border-l-0 border-border/80',
+        // Shadow and hover effects
+        'shadow-lg shadow-black/10 hover:shadow-xl hover:shadow-brand-500/10',
+        'text-muted-foreground hover:text-brand-500 hover:bg-accent/80',
+        'hover:border-brand-500/30',
+        'transition-all duration-200 ease-out',
+        'hover:w-10 active:scale-95'
+      )}
+      aria-label="Show sidebar"
+      data-testid="mobile-sidebar-toggle"
+    >
+      <PanelLeft className="w-4 h-4 pointer-events-none" />
+    </button>
+  );
+}

apps/ui/src/components/layout/sidebar/components/sidebar-header.tsx

@@ -1,15 +1,29 @@
-import { Folder, LucideIcon } from 'lucide-react';
+import { useState } from 'react';
+import { Folder, LucideIcon, X, Menu, Check } from 'lucide-react';
 import * as LucideIcons from 'lucide-react';
 import { cn, isMac } from '@/lib/utils';
 import { getAuthenticatedImageUrl } from '@/lib/api-fetch';
 import { isElectron, type Project } from '@/lib/electron';
+import { useIsCompact } from '@/hooks/use-media-query';
+import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover';
+import { useAppStore } from '@/store/app-store';
 
 interface SidebarHeaderProps {
   sidebarOpen: boolean;
   currentProject: Project | null;
+  onClose?: () => void;
+  onExpand?: () => void;
 }
 
-export function SidebarHeader({ sidebarOpen, currentProject }: SidebarHeaderProps) {
+export function SidebarHeader({
+  sidebarOpen,
+  currentProject,
+  onClose,
+  onExpand,
+}: SidebarHeaderProps) {
+  const isCompact = useIsCompact();
+  const [projectListOpen, setProjectListOpen] = useState(false);
+  const { projects, setCurrentProject } = useAppStore();
   // Get the icon component from lucide-react
   const getIconComponent = (): LucideIcon => {
     if (currentProject?.icon && currentProject.icon in LucideIcons) {
@@ -24,43 +38,141 @@ export function SidebarHeader({ sidebarOpen, currentProject }: SidebarHeaderProp
   return (
     <div
       className={cn(
-        'shrink-0 flex flex-col',
+        'shrink-0 flex flex-col relative',
         // Add padding on macOS Electron for traffic light buttons
         isMac && isElectron() && 'pt-[10px]'
       )}
     >
-      {/* Project name and icon display */}
-      {currentProject && (
-        <div
+      {/* Mobile close button - only visible on mobile when sidebar is open */}
+      {sidebarOpen && onClose && (
+        <button
+          onClick={onClose}
           className={cn(
-            'flex items-center gap-3 px-4 pt-3 pb-1',
-            !sidebarOpen && 'justify-center px-2'
+            'lg:hidden absolute top-3 right-3 z-10',
+            'flex items-center justify-center w-8 h-8 rounded-lg',
+            'bg-muted/50 hover:bg-muted',
+            'text-muted-foreground hover:text-foreground',
+            'transition-colors duration-200'
           )}
+          aria-label="Close navigation"
+          data-testid="sidebar-mobile-close"
         >
-          {/* Project Icon */}
-          <div className="shrink-0">
-            {hasCustomIcon ? (
-              <img
-                src={getAuthenticatedImageUrl(currentProject.customIconPath!, currentProject.path)}
-                alt={currentProject.name}
-                className="w-8 h-8 rounded-lg object-cover ring-1 ring-border/50"
-              />
-            ) : (
-              <div className="w-8 h-8 rounded-lg bg-brand-500/10 border border-brand-500/20 flex items-center justify-center">
-                <IconComponent className="w-5 h-5 text-brand-500" />
-              </div>
-            )}
-          </div>
-
-          {/* Project Name - only show when sidebar is open */}
-          {sidebarOpen && (
-            <div className="flex-1 min-w-0">
-              <h2 className="text-sm font-semibold text-foreground truncate">
-                {currentProject.name}
-              </h2>
-            </div>
+          <X className="w-5 h-5" />
+        </button>
+      )}
+      {/* Mobile expand button - hamburger menu to expand sidebar when collapsed on mobile */}
+      {!sidebarOpen && isCompact && onExpand && (
+        <button
+          onClick={onExpand}
+          className={cn(
+            'flex items-center justify-center w-10 h-10 mx-auto mt-2 rounded-lg',
+            'bg-muted/50 hover:bg-muted',
+            'text-muted-foreground hover:text-foreground',
+            'transition-colors duration-200'
           )}
-        </div>
+          aria-label="Expand navigation"
+          data-testid="sidebar-mobile-expand"
+        >
+          <Menu className="w-5 h-5" />
+        </button>
+      )}
+      {/* Project name and icon display - entire element clickable on mobile */}
+      {currentProject && (
+        <Popover open={projectListOpen} onOpenChange={setProjectListOpen}>
+          <PopoverTrigger asChild>
+            <button
+              className={cn(
+                'flex items-center gap-3 px-4 pt-3 pb-1 w-full text-left',
+                'rounded-lg transition-colors duration-150',
+                !sidebarOpen && 'justify-center px-2',
+                // Only enable click behavior on compact screens
+                isCompact && 'hover:bg-accent/50 cursor-pointer',
+                !isCompact && 'pointer-events-none'
+              )}
+              title={isCompact ? 'Switch project' : undefined}
+            >
+              {/* Project Icon */}
+              <div className="shrink-0">
+                {hasCustomIcon ? (
+                  <img
+                    src={getAuthenticatedImageUrl(
+                      currentProject.customIconPath!,
+                      currentProject.path
+                    )}
+                    alt={currentProject.name}
+                    className="w-8 h-8 rounded-lg object-cover ring-1 ring-border/50"
+                  />
+                ) : (
+                  <div className="w-8 h-8 rounded-lg bg-brand-500/10 border border-brand-500/20 flex items-center justify-center">
+                    <IconComponent className="w-5 h-5 text-brand-500" />
+                  </div>
+                )}
+              </div>
+
+              {/* Project Name - only show when sidebar is open */}
+              {sidebarOpen && (
+                <div className="flex-1 min-w-0">
+                  <h2 className="text-sm font-semibold text-foreground truncate">
+                    {currentProject.name}
+                  </h2>
+                </div>
+              )}
+            </button>
+          </PopoverTrigger>
+          <PopoverContent className="w-64 p-2" align="start" side="bottom" sideOffset={8}>
+            <div className="space-y-1">
+              <p className="text-xs font-medium text-muted-foreground px-2 py-1">Switch Project</p>
+              {projects.map((project) => {
+                const ProjectIcon =
+                  project.icon && project.icon in LucideIcons
+                    ? (LucideIcons as Record<string, LucideIcon>)[project.icon]
+                    : Folder;
+                const isActive = currentProject?.id === project.id;
+
+                return (
+                  <button
+                    key={project.id}
+                    onClick={() => {
+                      setCurrentProject(project);
+                      setProjectListOpen(false);
+                    }}
+                    className={cn(
+                      'w-full flex items-center gap-3 px-2 py-2 rounded-lg text-left',
+                      'transition-colors duration-150',
+                      isActive
+                        ? 'bg-brand-500/10 text-brand-500'
+                        : 'hover:bg-accent text-foreground'
+                    )}
+                  >
+                    {project.customIconPath ? (
+                      <img
+                        src={getAuthenticatedImageUrl(project.customIconPath, project.path)}
+                        alt={project.name}
+                        className="w-6 h-6 rounded object-cover ring-1 ring-border/50"
+                      />
+                    ) : (
+                      <div
+                        className={cn(
+                          'w-6 h-6 rounded flex items-center justify-center',
+                          isActive ? 'bg-brand-500/20' : 'bg-muted'
+                        )}
+                      >
+                        <ProjectIcon
+                          className={cn(
+                            'w-4 h-4',
+                            isActive ? 'text-brand-500' : 'text-muted-foreground'
+                          )}
+                        />
+                      </div>
+                    )}
+                    <span className="flex-1 text-sm truncate">{project.name}</span>
+                    {isActive && <Check className="w-4 h-4 text-brand-500" />}
+                  </button>
+                );
+              })}
+            </div>
+          </PopoverContent>
+        </Popover>
       )}
     </div>
   );

apps/ui/src/components/layout/sidebar/components/sidebar-navigation.tsx

@@ -21,7 +21,12 @@ export function SidebarNavigation({
   navigate,
 }: SidebarNavigationProps) {
   return (
-    <nav className={cn('flex-1 overflow-y-auto px-3 pb-2', sidebarOpen ? 'mt-1' : 'mt-1')}>
+    <nav
+      className={cn(
+        'flex-1 overflow-y-auto scrollbar-hide px-3 pb-2',
+        sidebarOpen ? 'mt-1' : 'mt-1'
+      )}
+    >
       {!currentProject && sidebarOpen ? (
         // Placeholder when no project is selected (only in expanded state)
         <div className="flex items-center justify-center h-full px-4">