Add content catalog search and filtering

Implement search and filtering capabilities for the content catalog.

Search Features:

• Full-text search by title, description
• Filter by category, status, date range
• Sort by popularity, date, rating
• Pagination support

Implementation:

• Add search endpoint GET /api/catalog/search
• Implement query parsing
• Add filter parameters
• Optimize database queries
• Add search result caching (Redis)
• Add search analytics

Performance Target: < 100ms p95 response time