feat: add shortcut for the countdown timer

src/components/menu/items/countdown.tsx

@@ -8,6 +8,11 @@ interface CountdownProps {
 
 export function Countdown({ open }: CountdownProps) {
   return (
-    <Item icon={<MdOutlineTimer />} label="Countdown Timer" onClick={open} />
+    <Item
+      icon={<MdOutlineTimer />}
+      label="Countdown Timer"
+      shortcut="Shift + C"
+      onClick={open}
+    />
   );
 }

src/components/menu/menu.tsx

@@ -77,6 +77,7 @@ export function Menu() {
   useHotkeys('shift+n', () => open('notepad'));
   useHotkeys('shift+p', () => open('pomodoro'));
   useHotkeys('shift+t', () => open('todo'));
+  useHotkeys('shift+c', () => open('countdown'));
   useHotkeys('shift+s', () => open('shareLink'), { enabled: !noSelected });
   useHotkeys('shift+alt+t', () => open('sleepTimer'));
 

src/components/modals/shortcuts/shortcuts.tsx

@@ -25,6 +25,10 @@ export function ShortcutsModal({ onClose, show }: ShortcutsModalProps) {
       keys: ['Shift', 'Alt', 'T'],
       label: 'Sleep Timer',
     },
+    {
+      keys: ['Shift', 'C'],
+      label: 'Countdown Timer',
+    },
     {
       keys: ['Shift', 'N'],
       label: 'Notepad',