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/admin/InvitationsListCard.tsx

@@ -1,4 +1,4 @@
-"use client";
+"use client";
 import { useEffect, useState } from "react";
 import { fetchClient } from "@/lib/api-client";
 
@@ -62,7 +62,7 @@ export default function InvitationsListCard() {
                     Code: <span className="font-mono px-1.5 py-0.5 rounded bg-muted">{inv.code}</span>
                   </div>
                   <div className="text-xs text-muted-foreground">
-                    Created: {new Date(inv.createdAt).toLocaleString()} · Expires: {new Date(inv.expiresAt).toLocaleString()}
+                    Created: {new Date(inv.createdAt).toLocaleString()} • Expires: {new Date(inv.expiresAt).toLocaleString()}
                   </div>
                 </div>
                 <div className="flex items-center gap-2 shrink-0">