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/layout/nav-item.tsx

@@ -1,4 +1,4 @@
-"use client"
+"use client"
 
 import Link from "next/link"
 import { usePathname } from "next/navigation"
@@ -65,4 +65,4 @@ export const NavItem: React.FC<NavItemProps> = ({ href, icon: Icon, children, on
       {children}
     </Link>
   )
-}
+}