feat(ui): add no-results empty state for Toolkit search (#105)

[soumyasekharshee265-ux]

Description

Added a no-results empty state for Toolkit search that appears only when a search query returns zero matches.

Related Issues

Closes #105

Type of Change

• 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)
• Documentation update

How Has This Been Tested?

• Ran npm run test — all 151 tests passing ✅
• Empty state appears only when search is active and tools exist
• Clear Search button restores the full tool list
• Initial load and error states are unaffected

Checklist

• My code follows the code style of this project
• 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
• My changes generate no new warnings