refactor: update theme management and enhance UI components

- Refactored theme imports in `preferences.ts` and `ThemeSelector.tsx` to use centralized `theme-config`.
- Added new CSS variables for special cards in `globals.css` to improve theme consistency.
- Enhanced `Header` and `TaskCard` components with theme dropdown functionality for better user experience.
- Updated `ThemeProvider` to support cycling through dark themes, improving theme selection flexibility.
- Cleaned up unused imports and streamlined component structures for better maintainability.

src/hooks/useKeyboardShortcuts.ts

@@ -0,0 +1,30 @@
+'use client';
+
+import { useEffect } from 'react';
+import { useTheme } from '@/contexts/ThemeContext';
+
+export function useKeyboardShortcuts() {
+  const { toggleTheme, cycleDarkThemes } = useTheme();
+
+  useEffect(() => {
+    const handleKeyDown = (event: KeyboardEvent) => {
+      // Cmd + T pour basculer entre light et le thème dark préféré
+      if ((event.metaKey || event.ctrlKey) && event.shiftKey && event.key === 'D') {
+        event.preventDefault();
+        toggleTheme();
+      }
+      
+      // Cmd + Shift + T pour faire tourner les thèmes dark
+      if ((event.metaKey || event.ctrlKey) && event.shiftKey && event.key === 'T') {
+        event.preventDefault();
+        cycleDarkThemes();
+      }
+    };
+
+    document.addEventListener('keydown', handleKeyDown);
+
+    return () => {
+      document.removeEventListener('keydown', handleKeyDown);
+    };
+  }, [toggleTheme, cycleDarkThemes]);
+}