feat: add terminal shortcuts panel for mobile (#411)

* feat: add terminal shortcuts panel for mobile users

Slide-out panel providing touch-friendly shortcut buttons (Esc, Tab,
Shift+Tab, Arrow Up/Down) and scroll-to-bottom for the terminal.
Integrates into the new modular shell architecture by exposing
terminalRef and wsRef from useShellRuntime hook and reusing the
existing sendSocketMessage utility.

Includes localization keys for en, ja, ko, and zh-CN.

* fix: replace dual touch/click handlers with unified pointer events

Prevents double-fire on touch devices by removing onTouchEnd handlers
and using a single onClick for all interactions (mouse, touch, keyboard).
onPointerDown with preventDefault handles focus steal prevention.
Also clears pending close timer before scheduling a new one to avoid
stale timeout overlap.

Addresses CodeRabbit review feedback on PR #411.

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Co-authored-by: Haileyesus <118998054+blackmammoth@users.noreply.github.com>

src/components/shell/hooks/useShellRuntime.ts

@@ -149,6 +149,8 @@ export function useShellRuntime({
 
   return {
     terminalContainerRef,
+    terminalRef,
+    wsRef,
     isConnected,
     isInitialized,
     isConnecting,