修正邀請碼問題

components/admin/user-management.tsx

@@ -457,9 +457,8 @@ export function UserManagement() {
     const newToken = Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15)
     const user = users.find((u) => u.id === userId)
     const role = (user as any)?.invitedRole || "user"
-    const newInvitationLink = isClient
-      ? `${window.location.origin}/register?token=${newToken}&email=${encodeURIComponent(email)}&role=${role}`
-      : `/register?token=${newToken}&email=${encodeURIComponent(email)}&role=${role}`
+    const baseUrl = process.env.NEXT_PUBLIC_APP_URL || (isClient ? window.location.origin : 'http://localhost:3000')
+    const newInvitationLink = `${baseUrl}/register?token=${newToken}&email=${encodeURIComponent(email)}&role=${role}`
 
     setUsers(
       users.map((user) =>