feat: add rich keyboard shortcuts with cheat sheet overlay

Comprehensive keybindings for power-user navigation:
- Ctrl+N: new session, Ctrl+W: archive session
- Ctrl+Tab / Ctrl+Shift+Tab: cycle between sessions
- Ctrl+,: open settings, Ctrl+/: shortcuts cheat sheet
- Ctrl+.: quick-approve pending tool call
- Ctrl+L: focus composer, Escape: cancel turn / close overlay

Centralized shortcut registry in lib/keyboardShortcuts.ts drives
both the cheat sheet panel and command palette shortcut badges.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/renderer/components/CommandPalette.tsx

@@ -4,6 +4,7 @@ import {
   Copy,
   FolderOpen,
   FolderPlus,
+  Keyboard,
   MessageSquare,
   Monitor,
   Moon,
@@ -20,6 +21,7 @@ import {
 import type { AppearanceTheme } from '@shared/domain/tooling';
 import { isScratchpadProject } from '@shared/domain/project';
 import type { WorkspaceState } from '@shared/domain/workspace';
+import { shortcutKeys } from '@renderer/lib/keyboardShortcuts';
 
 interface PaletteCommand {
   id: string;
@@ -47,6 +49,7 @@ export interface CommandPaletteProps {
   onArchiveSession: (sessionId: string, isArchived: boolean) => void;
   onAddProject: () => void;
   onOpenAppDataFolder: () => void;
+  onShowShortcuts: () => void;
 }
 
 /** Score how well `query` matches `text` (and optional `keywords`). 0 = no match. */
@@ -86,6 +89,7 @@ export function CommandPalette({
   onArchiveSession,
   onAddProject,
   onOpenAppDataFolder,
+  onShowShortcuts,
 }: CommandPaletteProps) {
   const [query, setQuery] = useState('');
   const [selectedIndex, setSelectedIndex] = useState(0);
@@ -151,6 +155,7 @@ export function CommandPalette({
         label: 'New Session',
         category: 'Actions',
         keywords: 'create start',
+        shortcut: shortcutKeys('new-session'),
         icon: <Plus className={ICON} />,
         action: () => onNewSession(defaultProjectId),
       });
@@ -187,7 +192,8 @@ export function CommandPalette({
         id: 'archive-session',
         label: 'Archive Session',
         category: 'Session',
-        keywords: 'archive hide remove',
+        keywords: 'archive hide remove close',
+        shortcut: shortcutKeys('close-session'),
         icon: <Archive className={ICON} />,
         action: () => onArchiveSession(selectedSession.id, true),
       });
@@ -221,6 +227,7 @@ export function CommandPalette({
       label: 'Open Settings',
       category: 'General',
       keywords: 'preferences config options',
+      shortcut: shortcutKeys('settings'),
       icon: <Settings className={ICON} />,
       action: onOpenSettings,
     });
@@ -241,7 +248,7 @@ export function CommandPalette({
       label: 'Toggle Terminal',
       category: 'General',
       keywords: 'terminal console shell command',
-      shortcut: 'Ctrl+`',
+      shortcut: shortcutKeys('toggle-terminal'),
       icon: <Terminal className={ICON} />,
       action: onToggleTerminal,
     });
@@ -255,6 +262,16 @@ export function CommandPalette({
       action: onOpenAppDataFolder,
     });
 
+    cmds.push({
+      id: 'keyboard-shortcuts',
+      label: 'Keyboard Shortcuts',
+      category: 'General',
+      keywords: 'keys keybindings hotkeys help cheatsheet',
+      shortcut: shortcutKeys('shortcut-help'),
+      icon: <Keyboard className={ICON} />,
+      action: onShowShortcuts,
+    });
+
     // ── Theme ──
     cmds.push({
       id: 'theme-dark',
@@ -287,7 +304,7 @@ export function CommandPalette({
     onSelectSession, onSelectProject, onNewSession, onCreateScratchpad,
     onOpenSettings, onOpenProjectSettings, onToggleTerminal, onSetTheme,
     onDuplicateSession, onPinSession, onArchiveSession, onAddProject,
-    onOpenAppDataFolder,
+    onOpenAppDataFolder, onShowShortcuts,
   ]);
 
   const filteredCommands = useMemo(() => {

src/renderer/components/KeyboardShortcutsPanel.tsx

@@ -0,0 +1,120 @@
+import { useEffect } from 'react';
+import { Keyboard } from 'lucide-react';
+
+import { shortcuts, type ShortcutDefinition } from '@renderer/lib/keyboardShortcuts';
+
+interface KeyboardShortcutsPanelProps {
+  onClose: () => void;
+}
+
+const categoryOrder = ['Navigation', 'Sessions', 'Workspace', 'General'] as const;
+
+function groupByCategory(defs: ShortcutDefinition[]): Map<string, ShortcutDefinition[]> {
+  const groups = new Map<string, ShortcutDefinition[]>();
+  for (const def of defs) {
+    const list = groups.get(def.category) ?? [];
+    list.push(def);
+    groups.set(def.category, list);
+  }
+  return groups;
+}
+
+export function KeyboardShortcutsPanel({ onClose }: KeyboardShortcutsPanelProps) {
+  // Escape to close — capture phase so it doesn't propagate
+  useEffect(() => {
+    const handleEscape = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') {
+        e.preventDefault();
+        e.stopImmediatePropagation();
+        onClose();
+      }
+    };
+    document.addEventListener('keydown', handleEscape, true);
+    return () => document.removeEventListener('keydown', handleEscape, true);
+  }, [onClose]);
+
+  const grouped = groupByCategory(shortcuts);
+
+  return (
+    <div
+      className="palette-backdrop-enter fixed inset-0 z-[70] flex items-center justify-center bg-[#07080e]/80 backdrop-blur-sm"
+      onClick={onClose}
+      role="dialog"
+      aria-modal="true"
+      aria-labelledby="shortcuts-title"
+    >
+      <div
+        className="palette-enter w-full max-w-lg overflow-hidden rounded-xl border border-[var(--color-border)] bg-[var(--color-surface-1)] shadow-[0_24px_80px_rgba(0,0,0,0.55)]"
+        onClick={(e) => e.stopPropagation()}
+      >
+        {/* Header */}
+        <div className="flex items-center gap-3 border-b border-[var(--color-border)] px-5 py-3.5">
+          <Keyboard className="size-4 text-[var(--color-text-accent)]" />
+          <h2
+            id="shortcuts-title"
+            className="font-display text-[14px] font-semibold text-[var(--color-text-primary)]"
+          >
+            Keyboard Shortcuts
+          </h2>
+          <span className="ml-auto text-[11px] text-[var(--color-text-muted)]">
+            Press <Kbd>Esc</Kbd> to close
+          </span>
+        </div>
+
+        {/* Body — two-column grid of categories */}
+        <div className="grid grid-cols-2 gap-x-6 gap-y-5 px-5 py-4">
+          {categoryOrder.map((cat) => {
+            const items = grouped.get(cat);
+            if (!items?.length) return null;
+            return (
+              <div key={cat}>
+                <h3 className="mb-2 text-[11px] font-medium uppercase tracking-wider text-[var(--color-text-muted)]">
+                  {cat}
+                </h3>
+                <ul className="space-y-1.5">
+                  {items.map((item) => (
+                    <li
+                      key={item.id}
+                      className="flex items-center justify-between gap-3 text-[12.5px]"
+                    >
+                      <span className="truncate text-[var(--color-text-secondary)]">
+                        {item.label}
+                      </span>
+                      <ShortcutBadge keys={item.keys} />
+                    </li>
+                  ))}
+                </ul>
+              </div>
+            );
+          })}
+        </div>
+
+        {/* Footer */}
+        <div className="border-t border-[var(--color-border)] px-5 py-2.5 text-[11px] text-[var(--color-text-muted)]">
+          Tip: Use the command palette for even more actions
+        </div>
+      </div>
+    </div>
+  );
+}
+
+/** Inline keyboard key cap. */
+function Kbd({ children }: { children: React.ReactNode }) {
+  return (
+    <kbd className="rounded border border-[var(--color-border)] bg-[var(--color-surface-0)] px-1.5 py-0.5 font-mono text-[10px] text-[var(--color-text-muted)]">
+      {children}
+    </kbd>
+  );
+}
+
+/** Renders a compound shortcut like "Ctrl+Shift+Tab" as joined key caps. */
+function ShortcutBadge({ keys }: { keys: string }) {
+  const parts = keys.split('+');
+  return (
+    <span className="flex shrink-0 items-center gap-0.5">
+      {parts.map((part, i) => (
+        <Kbd key={i}>{part}</Kbd>
+      ))}
+    </span>
+  );
+}