Implements Roadmap 2.5b: new /compare command lets players compare two
cards of the same type (batter vs batter or pitcher vs pitcher) in a
side-by-side embed with directional delta arrows (▲▼═).
- cogs/compare.py: new CompareCog with /compare slash command and
player_autocomplete on both params; fetches battingcard/pitchingcard
data from API; validates type compatibility; sends public embed
- tests/test_compare_command.py: 30 unit tests covering _delta_arrow,
_is_pitcher, batter/pitcher embed builders, type mismatch error, and
edge cases (None stats, tied values)
- paperdynasty.py: registers cogs.compare in COGS list
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
