Add CSV export for orders and update UI symbols

Introduces an exportOrdersToCSV function in lib/api-client.ts to allow exporting orders by status as a CSV file. Updates various UI components to use the '•' (bullet) symbol instead of '·' (middle dot) and replaces some emoji/unicode characters for improved consistency and compatibility. Also normalizes the 'use client' directive to include a BOM in many files.

components/dashboard/promotions/PromotionDetailsModal.tsx

@@ -1,4 +1,4 @@
-'use client';
+'use client';
 
 import { useState, useEffect } from 'react';
 import { 
@@ -222,7 +222,7 @@ export default function PromotionDetailsModal({
                     <div className="flex items-center justify-between mb-2">
                       <span className="text-sm font-medium">Current Usage</span>
                       <span className="text-sm text-muted-foreground">
-                        {promotion.usageCount} / {promotion.maxUsage || '∞'}
+                        {promotion.usageCount} / {promotion.maxUsage || 'Ôê×'}
                       </span>
                     </div>
                     <div className="w-full bg-gray-200 rounded-full h-2">
@@ -382,4 +382,4 @@ export default function PromotionDetailsModal({
       </DialogContent>
     </Dialog>
   );
-}
+}