feat: add duplicate email detection via auth hook with fallback

- Add before-user-created hook function for server-side duplicate email detection
- Implement fallback detection using identities array check (Supabase limitation)
- Update signUpWithPassword to detect duplicate emails via hook errors or empty identities
- Add error handling in login page to show duplicate email errors and auto-switch to login mode
- Add auth hook setup documentation and test scripts
- Add password reset and update password flows
- Add email templates for signup confirmation and password reset

components/ui/bento-grid.tsx

@@ -35,7 +35,7 @@ const BentoCard = ({
   name: string;
   className: string;
   background: ReactNode;
-  Icon: any;
+  Icon?: any;
   description: string;
   href: string;
   cta: string;
@@ -53,7 +53,7 @@ const BentoCard = ({
   >
     <div>{background}</div>
     <div className="pointer-events-none z-10 flex transform-gpu flex-col gap-1 p-6 transition-all duration-300 group-hover:-translate-y-10">
-      <Icon className="h-12 w-12 origin-left transform-gpu text-neutral-700 transition-all duration-300 ease-in-out group-hover:scale-75" />
+      {Icon && <Icon className="h-12 w-12 origin-left transform-gpu text-neutral-700 transition-all duration-300 ease-in-out group-hover:scale-75" />}
       <h3 className="text-xl font-semibold text-neutral-700 dark:text-neutral-300">
         {name}
       </h3>