- Add POST /case/{id}/update route for editing case fields (status, case_type, description, open_date, close_date)
- Add POST /case/{id}/close route to set status='closed' and close_date=current date
- Add POST /case/{id}/reopen route to set status='active' and clear close_date
- Update case.html template with edit form, success/error messaging, and action buttons
- Include comprehensive validation for dates and status values
- Add proper error handling with session-based error storage
- Preserve existing view content and styling consistency
