RivalsData API 1.2.1

Player class statistics now accept a numeric season ID or season="all" for
combined all-seasons data, matching the player hero summary selector.

player.stats.classes(season=20)
player.stats.classes(season="all")

The detailed player.stats.heroes method and MCP get_player_stats tool also
accept season="all". The wrapper sends the upstream all-seasons selector
(-1); omitting the season preserves the endpoint default.

Validation: all 16 tests pass, including selector forwarding and the MCP input
schema; Ruff checks and source/wheel builds pass.