feat: add procurement frontend templates and styles
Stage 6 - Frontend Implementation:
- Add procurement.css with iOS-style components
- Add dashboard, request_list, request_detail, request_form templates
- Add equipment_list, equipment_detail templates
- Add status badges and filters partials
- Add JS handlers for dashboard, requests and equipment
- Add procurement link to sidebar navigation
- Configure separate URL namespaces (procurement for API, procurement_frontend for views)
All 66 tests passing.