Add keyboard shortcut rebinding with string-based format and sectioned settings UI

- Parse/format shortcut strings ("Cmd+Shift+O") bidirectionally via shortcut-string.ts
- Convert all 60+ bindings from structured KeyCombo objects to declarative strings
- Add keyboard shortcut overrides storage (AsyncStorage + React Query)
- Wire overrides into the keyboard shortcut resolution pipeline
- Add sectioned settings layout with sidebar on desktop, single scroll on mobile
- Add keyboard shortcuts settings section with rebind/reset UI and key capture
- Create useShortcutKeys hook so tooltip shortcut displays update on rebind
- Replace hardcoded shortcut displays in agent-input-area, left-sidebar, command center

packages/app/src/hooks/use-shortcut-keys.ts

@@ -0,0 +1,26 @@
+import { useMemo } from "react";
+import type { ShortcutKey } from "@/utils/format-shortcut";
+import { comboStringToShortcutKeys } from "@/keyboard/shortcut-string";
+import { getBindingIdForAction, getDefaultKeysForAction } from "@/keyboard/keyboard-shortcuts";
+import { useKeyboardShortcutOverrides } from "@/hooks/use-keyboard-shortcut-overrides";
+import { getShortcutOs } from "@/utils/shortcut-platform";
+import { getIsDesktop } from "@/constants/layout";
+
+export function useShortcutKeys(actionId: string): ShortcutKey[] | null {
+  const { overrides } = useKeyboardShortcutOverrides();
+  const isMac = getShortcutOs() === "mac";
+  const isDesktop = getIsDesktop();
+
+  return useMemo(() => {
+    const platform = { isMac, isDesktop };
+    const bindingId = getBindingIdForAction(actionId, platform);
+    if (!bindingId) return null;
+
+    const override = overrides[bindingId];
+    if (override) {
+      return comboStringToShortcutKeys(override);
+    }
+
+    return getDefaultKeysForAction(actionId, platform);
+  }, [actionId, overrides, isMac, isDesktop]);
+}