AuthErrorBanner does not support dark mode

[dotsdl]

Problem

Every other component in the app uses dark: Tailwind variants, but AuthErrorBanner hardcodes light-mode-only colors:

<div className={`border rounded-lg p-4 ${
  isAuthError
    ? 'bg-yellow-50 border-yellow-200'
    : 'bg-red-50 border-red-200'
}`}>
  <p className={isAuthError ? 'text-yellow-800' : 'text-red-600'}>

This makes the banner look broken against dark backgrounds.

Suggested fix

Add dark: variants consistent with the rest of the app (e.g., dark:bg-yellow-900/20 dark:border-yellow-800 dark:text-yellow-300).