ENHANCEMENT: Add domain-specific and lifecycle status filters

[jt14den]

Goal

Expand filtering options to include domain tags (Research Software, Data Science, etc.) and lifecycle status.

Tasks

• Identify domain categories from CSV data
• Add domain field to lesson type definition
• Create domain filter dropdown in LessonFilter component
• Add lifecycle status filter (if available in data)
• Update filter logic to handle multiple filter combinations
• Add filter state persistence (URL params or localStorage)
• Add Clear all filters button
• Show active filter count
• Test filter performance with all combinations

Data Dependencies

Check if domain/lifecycle fields exist in CSV or need to be added to Google Sheet first.

Reference

See STUDENT_README.md Phase 2 Enhancement #4