Changed forced_action from single item to FIFO queue to support
scenarios where multiple forced actions are needed simultaneously:
- forced_actions: list[ForcedAction] replaces forced_action: ForcedAction | None
- Added queue management methods:
- has_forced_action() - check if queue has pending actions
- get_current_forced_action() - get first action without removing
- add_forced_action(action) - add to end of queue
- pop_forced_action() - remove and return first action
- clear_forced_actions() - clear all pending actions
- Updated engine, turn_manager, rules_validator, and visibility filter
- Added 8 new tests for forced action queue including double knockout scenario
This fixes the bug where simultaneous knockouts (e.g., mutual poison damage)
would lose one player's select_active action due to overwriting.
795 tests passing.
9432499018