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/modals/product-modal.tsx

@@ -1,4 +1,4 @@
-"use client";
+"use client";
 
 import { useState, useEffect } from "react";
 import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from "@/components/ui/dialog";
@@ -320,7 +320,7 @@ const ProductBasicInfo: React.FC<{
     </div>
 
     <div className="bg-background rounded-lg border border-border p-4">
-      <h3 className="text-sm font-medium mb-4">💰 Cost & Profit Tracking</h3>
+      <h3 className="text-sm font-medium mb-4">­ƒÆ░ Cost & Profit Tracking</h3>
       <p className="text-xs text-muted-foreground mb-4">
         Track your costs to automatically calculate profit margins and markup percentages.
       </p>
@@ -474,4 +474,4 @@ const UnitTypeSelect: React.FC<{
       </Button>
     </div>
   </div>
-);
+);