fix : made ErrorBoundary fallback UI adapt to light mode

[tmdeveloper007]

Summary of What Has Been Done

The ErrorBoundary.jsx component used hardcoded dark-mode colors for the error fallback UI. This has been updated to use dark-mode-aware Tailwind classes so the error page is readable in both light and dark modes.

Changes Made

1. frontend/src/components/ErrorBoundary.jsx:
   • Outer container: bg-gray-900 + text-white → bg-gray-100 dark:bg-gray-900 + text-gray-900 dark:text-white
   • Card container: bg-gray-800 → bg-white dark:bg-gray-800, border-gray-700 → border-gray-200 dark:border-gray-700
   • Title: text-gray-100 → text-gray-900 dark:text-gray-100
   • Description: text-gray-400 → text-gray-500 dark:text-slate-300
   • Error display box: bg-gray-950 → bg-gray-100 dark:bg-gray-950, border-gray-700/50 → border-gray-200 dark:border-gray-700/50, text-red-400/90 → text-red-500 dark:text-red-400/90
   • Return Home button: bg-gray-700 → bg-gray-300 dark:bg-gray-700, text-white → text-gray-800 dark:text-gray-100, hover states updated

Impact it Made

• Error fallback page is now readable in both light and dark modes
• Consistent user experience regardless of theme preference
• Matches the dark-mode-aware pattern used throughout the rest of the codebase

Closes #2023

Note: Please assign this PR to the tmdeveloper007 account.