Showing last year Pull Requests, Members, Mentors

### Expected Behavior
Showing last year statistics, to get a overview of the competition from low-level perspective.

The issue requests showing last year's statistics for pull requests, members, and mentors. Start by examining the existing CLI code to understand how it currently fetches and displays data. Look for API calls or data sources related to CodeHeat. Determine what 'last year' means (calendar year, rolling year) and how to aggregate the statistics. Check if there are existing tests for data display to understand the expected output format.

Written by the indexing model from the issue text.