2ca87af1b5
Game client Lua expects GET /decks to return a map of
{deck_index: {name, cards}} not a flat array. Array format caused
self.decks to be set to wrong structure, breaking deck lookups and
triggering phantom deck creation on every interaction.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>