feat: Refactor AppShell and Header components, enhance memory management UI, and align API endpoints

- Removed defaultCollapsed prop from AppShell and set sidebar to be collapsed by default.
- Updated Header component to remove mobile menu toggle and added a history entry button.
- Refactored ExplorationsSection to streamline data extraction and improve UI rendering.
- Added new messages for GitHub sync success and error handling in issues.
- Implemented View Memory Dialog for better memory content viewing and editing.
- Enhanced FlowToolbar to auto-create flows and improved save functionality.
- Conducted a frontend audit for API endpoint alignment with backend implementations.

ccw/frontend/src/components/layout/AppShell.tsx

@@ -17,8 +17,6 @@ import { useWorkflowStore } from '@/stores/workflowStore';
 import { useWebSocketNotifications, useWebSocket } from '@/hooks';
 
 export interface AppShellProps {
-  /** Initial sidebar collapsed state */
-  defaultCollapsed?: boolean;
   /** Callback for refresh action */
   onRefresh?: () => void;
   /** Whether refresh is in progress */
@@ -31,7 +29,6 @@ export interface AppShellProps {
 const SIDEBAR_COLLAPSED_KEY = 'ccw-sidebar-collapsed';
 
 export function AppShell({
-  defaultCollapsed = false,
   onRefresh,
   isRefreshing = false,
   children,
@@ -74,13 +71,14 @@ export function AppShell({
     setWorkspaceInitialized(true);
   }, [isWorkspaceInitialized, projectPath, location.search, switchWorkspace]);
 
-  // Sidebar collapse state (persisted)
+  // Sidebar collapse state – default to collapsed (hidden)
   const [sidebarCollapsed, setSidebarCollapsed] = useState(() => {
     if (typeof window !== 'undefined') {
       const stored = localStorage.getItem(SIDEBAR_COLLAPSED_KEY);
-      return stored ? JSON.parse(stored) : defaultCollapsed;
+      // Default to collapsed (true) if no persisted value
+      return stored !== null ? JSON.parse(stored) : true;
     }
-    return defaultCollapsed;
+    return true;
   });
 
   // Mobile sidebar open state
@@ -117,16 +115,14 @@ export function AppShell({
     localStorage.setItem(SIDEBAR_COLLAPSED_KEY, JSON.stringify(sidebarCollapsed));
   }, [sidebarCollapsed]);
 
-  // Close mobile sidebar on route change or resize
+  // Close mobile sidebar on resize
   useEffect(() => {
     const handleResize = () => {
       if (window.innerWidth >= 768) {
         setMobileOpen(false);
       }
     };
-
     window.addEventListener('resize', handleResize);
-    // Cleanup: Remove event listener on unmount to prevent memory leak
     return () => window.removeEventListener('resize', handleResize);
   }, []);
 
@@ -174,7 +170,7 @@ export function AppShell({
 
       {/* Main layout - sidebar + content */}
       <div className="flex flex-1 overflow-hidden">
-        {/* Sidebar */}
+        {/* Sidebar - collapsed by default */}
         <Sidebar
           collapsed={sidebarCollapsed}
           onCollapsedChange={handleCollapsedChange}
@@ -186,7 +182,6 @@ export function AppShell({
         <MainContent
           className={cn(
             'transition-all duration-300',
-            // Add left margin on desktop to account for fixed sidebar
             sidebarCollapsed ? 'md:ml-16' : 'md:ml-64'
           )}
         >

ccw/frontend/src/components/layout/Header.tsx

@@ -8,7 +8,6 @@ import { Link } from 'react-router-dom';
 import { useIntl } from 'react-intl';
 import {
   Workflow,
-  Menu,
   Moon,
   Sun,
   RefreshCw,
@@ -17,6 +16,7 @@ import {
   LogOut,
   Terminal,
   Bell,
+  Clock,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { Button } from '@/components/ui/Button';
@@ -27,8 +27,6 @@ import { useCliStreamStore, selectActiveExecutionCount } from '@/stores/cliStrea
 import { useNotificationStore } from '@/stores';
 
 export interface HeaderProps {
-  /** Callback to toggle mobile sidebar */
-  onMenuClick?: () => void;
   /** Callback for refresh action */
   onRefresh?: () => void;
   /** Whether refresh is in progress */
@@ -38,7 +36,6 @@ export interface HeaderProps {
 }
 
 export function Header({
-  onMenuClick,
   onRefresh,
   isRefreshing = false,
   onCliMonitorClick,
@@ -65,19 +62,8 @@ export function Header({
       className="flex items-center justify-between px-4 md:px-5 h-14 bg-card border-b border-border sticky top-0 z-50 shadow-sm"
       role="banner"
     >
-      {/* Left side - Menu button (mobile) and Logo */}
+      {/* Left side - Logo */}
       <div className="flex items-center gap-3">
-        {/* Mobile menu toggle */}
-        <Button
-          variant="ghost"
-          size="icon"
-          className="md:hidden"
-          onClick={onMenuClick}
-          aria-label={formatMessage({ id: 'common.aria.toggleNavigation' })}
-        >
-          <Menu className="w-5 h-5" />
-        </Button>
-
         {/* Logo / Brand */}
         <Link
           to="/"
@@ -91,6 +77,19 @@ export function Header({
 
       {/* Right side - Actions */}
       <div className="flex items-center gap-2">
+        {/* History entry */}
+        <Button
+          variant="ghost"
+          size="sm"
+          asChild
+          className="gap-2"
+        >
+          <Link to="/history">
+            <Clock className="h-4 w-4" />
+            <span className="hidden sm:inline">{formatMessage({ id: 'navigation.main.history' })}</span>
+          </Link>
+        </Button>
+
         {/* CLI Monitor button */}
         <Button
           variant="ghost"