fix: remove Firebase dependencies for web3-first static export

- Remove Firebase auth components (LoginPanel, SignupPanel)
- Remove Firebase-dependent checkout pages
- Replace with web3 wallet connect placeholder
- Pure blockchain backend, no Firebase needed

src/app/checkout/page.tsx

@@ -1,17 +0,0 @@
-import React from 'react'
-
-import { cn } from '@hanzo/ui/util'
-import { CheckoutPanel, Main } from '@luxfi/ui'
-
-const Page: React.FC = () =>  (
-  <Main /* id='CHECKOUT_MAIN' */ headerSpace={false} standardWidth={false} className={cn(
-    '!px-0 !py-0',
-    'w-full h-[100vh]',
-    'animate-in md:zoom-in-90',
-    'shadow-lg bg-background'
-  )}>
-    <CheckoutPanel clx='w-full h-full' />
-  </Main>
-)
-
-export default Page