refactor: remove non-functional Ctrl+A select-all shortcut

Removes the Ctrl+A keyboard shortcut and associated select-all functionality
that was not working properly.

Changes:
- Remove select-all shortcut definition from useGlobalShortcuts
- Remove "Select All" menu item from View menu
- Remove handleSelectAll stub function from App.tsx
- Clean up onSelectAll prop from MenuBar component

The select-all feature was dysfunctional (only logging to console) and
not properly implemented, so it has been removed entirely.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/App.tsx

@@ -75,12 +75,6 @@ function AppContent() {
     fitView({ padding: 0.2, duration: 300 });
   }, [fitView]);
 
-  const handleSelectAll = useCallback(() => {
-    // This will be implemented in GraphEditor
-    // For now, we'll just document it
-    console.log("Select All - to be implemented");
-  }, []);
-
   // Setup global keyboard shortcuts
   useGlobalShortcuts({
     onUndo: undo,
@@ -89,7 +83,6 @@ function AppContent() {
     onOpenDocumentManager: () => setShowDocumentManager(true),
     onOpenHelp: () => setShowKeyboardHelp(true),
     onFitView: handleFitView,
-    onSelectAll: handleSelectAll,
     onFocusSearch: () => leftPanelRef.current?.focusSearch(),
   });
 
@@ -133,7 +126,6 @@ function AppContent() {
       <MenuBar
         onOpenHelp={() => setShowKeyboardHelp(true)}
         onFitView={handleFitView}
-        onSelectAll={handleSelectAll}
         onExport={exportCallbackRef.current || undefined}
       />
 

src/components/Menu/MenuBar.tsx

@@ -24,11 +24,10 @@ import type { ExportOptions } from '../../utils/graphExport';
 interface MenuBarProps {
   onOpenHelp?: () => void;
   onFitView?: () => void;
-  onSelectAll?: () => void;
   onExport?: (format: 'png' | 'svg', options?: ExportOptions) => Promise<void>;
 }
 
-const MenuBar: React.FC<MenuBarProps> = ({ onOpenHelp, onFitView, onSelectAll, onExport }) => {
+const MenuBar: React.FC<MenuBarProps> = ({ onOpenHelp, onFitView, onExport }) => {
   const [activeMenu, setActiveMenu] = useState<string | null>(null);
   const [showDocumentManager, setShowDocumentManager] = useState(false);
   const [showNodeConfig, setShowNodeConfig] = useState(false);
@@ -415,18 +414,6 @@ const MenuBar: React.FC<MenuBarProps> = ({ onOpenHelp, onFitView, onSelectAll, o
                     <span className="text-xs text-gray-400">{getShortcutLabel('fit-view')}</span>
                   )}
                 </button>
-                <button
-                  onClick={() => {
-                    onSelectAll?.();
-                    closeMenu();
-                  }}
-                  className="w-full text-left px-4 py-2 text-sm text-gray-700 hover:bg-gray-100 flex items-center justify-between"
-                >
-                  <span>Select All</span>
-                  {getShortcutLabel('select-all') && (
-                    <span className="text-xs text-gray-400">{getShortcutLabel('select-all')}</span>
-                  )}
-                </button>
               </div>
             )}
           </div>

src/hooks/useGlobalShortcuts.ts

@@ -17,7 +17,6 @@ interface UseGlobalShortcutsOptions {
   onRedo?: () => void;
   onOpenHelp?: () => void;
   onFitView?: () => void;
-  onSelectAll?: () => void;
   onFocusSearch?: () => void;
 }
 
@@ -143,15 +142,6 @@ export function useGlobalShortcuts(options: UseGlobalShortcutsOptions = {}) {
       },
 
       // Selection
-      {
-        id: "select-all",
-        description: "Select All",
-        key: "a",
-        ctrl: true,
-        handler: () => options.onSelectAll?.(),
-        category: "Selection",
-        enabled: !!options.onSelectAll,
-      },
       {
         id: "deselect-all",
         description: "Deselect All",