enhancement(ui): standardize user-facing error feedback across admin workflows

[Yash-Marathe91]

…workflowsResolves #245

What was the problem?

During the review of the admin panel workflows (save, update, delete, upload, export, etc.), it was noticed that failed operations were only logging to console.error(). While this is useful for developers debugging via the browser console, users were left without any visible indication of failure, causing confusion about whether their actions succeeded or failed.

How was it solved?

This PR standardizes the error feedback mechanism across the entire RestroHub-FrontEnd/src/components/admin directory:

• Imported react-hot-toast across 33 admin components.
• Injected toast.error('...') notifications alongside the existing console.error() statements in catch blocks.
• Preserved the existing console.error() logs to ensure debugging is not compromised.
• Improved overall UX transparency, ensuring that users are instantly notified of failed operations in real-time.

Impact

• UX Improvement: Admins now receive immediate visual feedback on operation failures (e.g., when saving website configurations, modifying personal data, managing menu items, or failing to fetch live orders).
• Consistent Error Handling: Aligns the rest of the admin interface with the notification standards established in #227.

Checklist

• Scanned all admin components for silent catch blocks.
• Added toast.error without removing console.error.
• Tested frontend compilation to ensure all react-hot-toast imports are valid.
• Followed CONTRIBUTING.md guidelines.