Implement search and filter logic

[Dustin-Reyes]

Add client-side search functionality across menu items.

Tasks:

• Create src/hooks/useMenuSearch.js
• Implement multi-field search (name, description, tags)
• Use useMemo for performance
• Return filtered items and categories
• Handle empty results
• Add debouncing if needed

Acceptance Criteria:

• Search works across name, description, tags
• Results update in real-time
• Performance is smooth
• Empty categories hidden when filtering

Milestone: Integration (Phase 4)