feat: Improve toast messages and errors

[github-roushan]

Describe Your Changes

• Add preflight option to get metadata and actionable errors
• Add Token Validation Timeout
• Improve Various Toasts for download action
• Improve validate button ux

Fixes Issues

• Closes #6861

Self Checklist

• [ ] Added relevant comments, esp in complex areas
• [ ] Updated docs (for bug fixes / features)
• [ ] Created issues for follow-up changes or refactoring needed