RivalsData API 1.2.0

Adds calculated player statistics for tank, support, and DPS through
player.stats.classes(season=...) and the MCP get_player_stats tool with
category="classes".

• Returns separate competitive and quickplay totals for games, wins, losses,
  available MVP/SVP counts, and win rates calculated from summed wins/losses.
• Includes official role names, contributing hero IDs, and excluded records
  for unknown classes or incomplete win/loss counts.
• Supports Deadpool's separate tank, DPS, and support IDs and corrects the
  previously reversed Angela and Daredevil name mappings.
• Adds typed class response models and exports HERO_CLASSES and hero_class.
• Documents Camoufox findings on match-level character playtime. No cumulative
  playtime feature is included.

Class totals count hero participation and may count one match more than once
when a player switches heroes. Empty modes have a null win rate.

Validation: 10 mocked tests pass; Ruff checks and source/wheel builds pass.