fix(frontend): add error state and user feedback to block input fields

[PranavBhatP]

Motivation

Added error state for block input fields and provides real-time user feedback on regex and text inputs.

Fixes #167

Type of change

Please delete options that are not relevant.

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Checklist:

• [X] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation (Storybook)
• [ ] I have added unit tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes