Feat: Remove terminal warnings

Hi team 👋

This PR significantly reduces the number of terminal warnings displayed when starting the project. These warnings created noise, making it difficult to spot new, critical warnings.

Key Changes

• Removed unused imports across various files.
• Fixed incorrect/legacy CSS syntax in a few older .css files.
• Removed unnecessary null checks.

The only valid null check identified was for the mPeer property; I updated its type definition in Solution type to reflect its possible nullability, keeping the check in place.

Testing & Risk I have manually tested the application's core functionality after these changes and observed no issues.

• Reviewer Focus: Please pay special attention to the areas where null checks were removed to confirm the types are indeed non-nullable in those contexts.

Known Remaining Issue One warning related to angular.min.js still remains. I've left this minified, third-party file untouched.

Thanks for the review!