Add reset password page and update VendorsCard

Introduces a new password reset page with token validation and form handling. Removes the optional email field from the Vendor interface and its display in the VendorsCard component.

components/admin/VendorsCard.tsx

@@ -5,7 +5,6 @@ import { fetchClient } from "@/lib/api-client";
 interface Vendor {
   _id: string;
   username: string;
-  email?: string;
   isAdmin: boolean;
   createdAt: string;
   lastLogin?: string;
@@ -63,7 +62,6 @@ export default function VendorsCard() {
                 <div className="space-y-1">
                   <div className="font-medium">{vendor.username}</div>
                   <div className="text-xs text-muted-foreground">
-                    {vendor.email && `${vendor.email} · `}
                     Created: {new Date(vendor.createdAt).toLocaleDateString()}
                     {vendor.lastLogin && ` · Last login: ${new Date(vendor.lastLogin).toLocaleDateString()}`}
                   </div>