Implements the main public API for the core game engine:
- create_game(): deck validation, shuffling, dealing hands
- execute_action(): validates and executes all 11 action types
- start_turn()/end_turn(): turn management integration
- get_visible_state(): hidden info filtering for clients
- handle_timeout(): timeout handling for turn limits
Integrates turn_manager, rules_validator, win_conditions, and
visibility filter into a cohesive orchestration layer.
22 integration tests covering game creation, action execution,
visibility filtering, and error handling.
711 tests passing (29/32 tasks complete)