docs: Update keyboard shortcuts and add to Command Palette

Author: AmirMohammad Cheraghali

src/App.tsx

@@ -20,7 +20,7 @@ import type { PDBMetadata, Measurement, MeasurementTextColor } from './types';
 import {
   Camera, RefreshCw, Upload,
   Settings, Zap, Activity, Grid3X3, Palette,
-  Share2, Save, FolderOpen, Video, Ruler, Maximize2, Star
+  Share2, Save, FolderOpen, Video, Ruler, Maximize2, Star, Undo2, Redo2
 } from 'lucide-react';
 import { startOnboardingTour } from './components/TourGuide';
 import { ToastContainer } from './components/Toast';
@@ -1007,6 +1007,22 @@ function App() {
       category: 'View',
       perform: handleResetView
     },
+    {
+      id: 'undo',
+      label: 'Undo',
+      icon: Undo2,
+      shortcut: 'Cmd/Ctrl+Z',
+      category: 'Edit',
+      perform: () => { if (canUndo) undo(); }
+    },
+    {
+      id: 'redo',
+      label: 'Redo',
+      icon: Redo2,
+      shortcut: 'Shift+Cmd/Ctrl+Z',
+      category: 'Edit',
+      perform: () => { if (canRedo) redo(); }
+    },
     {
       id: 'toggle-pub-mode',
       label: isPublicationMode ? 'Exit Publication Mode' : 'Enter Publication Mode',

src/components/HelpGuide.tsx

@@ -221,6 +221,8 @@ export const HelpGuide: React.FC<{ isVisible?: boolean }> = ({ isVisible = true
                     <div className="flex justify-between text-neutral-300"><span>Full Screen</span> <kbd className="font-mono bg-neutral-800 px-1.5 rounded text-neutral-400">F</kbd></div>
                     <div className="flex justify-between text-neutral-300"><span>Theme Toggle</span> <kbd className="font-mono bg-neutral-800 px-1.5 rounded text-neutral-400">T</kbd></div>
                     <div className="flex justify-between text-neutral-300"><span>Screenshot</span> <kbd className="font-mono bg-neutral-800 px-1.5 rounded text-neutral-400">S</kbd></div>
+                    <div className="flex justify-between text-neutral-300"><span>Undo</span> <kbd className="font-mono bg-neutral-800 px-1.5 rounded text-neutral-400">⌘Z / Ctrl+Z</kbd></div>
+                    <div className="flex justify-between text-neutral-300"><span>Redo</span> <kbd className="font-mono bg-neutral-800 px-1.5 rounded text-neutral-400">⇧⌘Z / Shift+Ctrl+Z</kbd></div>
 
                     <div className="col-span-2 pb-1 mb-1 mt-3 border-b border-neutral-800 font-bold text-neutral-400 uppercase tracking-widest text-[10px]">Views</div>
                     <div className="flex justify-between text-neutral-300"><span>Reset View</span> <kbd className="font-mono bg-neutral-800 px-1.5 rounded text-neutral-400">R</kbd></div>