feat: enhance theme management and customization options

- Added support for multiple themes (dracula, monokai, nord, gruvbox, tokyo_night, catppuccin, rose_pine, one_dark, material, solarized) in the application.
- Updated `setTheme` function to accept the new `Theme` type, allowing for more flexible theme selection.
- Introduced `ThemeSelector` component in GeneralSettingsPage for user-friendly theme selection.
- Modified `ThemeProvider` to handle user preferred themes and improved theme toggling logic.
- Updated CSS variables in `globals.css` to support new themes, enhancing visual consistency across the app.

src/actions/preferences.ts

@@ -1,7 +1,7 @@
 'use server';
 
 import { userPreferencesService } from '@/services/core/user-preferences';
-import { KanbanFilters, ViewPreferences, ColumnVisibility, TaskStatus } from '@/lib/types';
+import { KanbanFilters, ViewPreferences, ColumnVisibility, TaskStatus, Theme } from '@/lib/types';
 import { revalidatePath } from 'next/cache';
 
 /**
@@ -117,9 +117,9 @@ export async function toggleObjectivesCollapse(): Promise<{
 }
 
 /**
- * Change le thème (light/dark)
+ * Change le thème (light/dark/dracula/monokai/nord)
  */
-export async function setTheme(theme: 'light' | 'dark'): Promise<{
+export async function setTheme(theme: Theme): Promise<{
   success: boolean;
   error?: string;
 }> {