feat(bd-38s): Add comprehensive tests for CollisionAlert component
The CollisionAlert React component was already fully implemented in
src/web/frontend/src/components/CollisionAlert.tsx. This commit adds
comprehensive test coverage including:
- Rendering tests (visibility, empty state, counts)
- Severity grouping (critical/error, warning, info)
- Type icons (F, B, T for file, bead, task)
- Severity icons (!!!, !!, !, i)
- Acknowledgment functionality
- Detail view display
- Worker display (count vs names)
- Title truncation
- CSS class application
- Selection handling
Co-Authored-By: Claude Worker <noreply@anthropic.com>