Add comprehensive engine tests and fix action field name bugs
Bug fixes in engine.py:
- PlayPokemonAction: card_id -> card_instance_id
- PlayTrainerAction: card_id -> card_instance_id
- UseAbilityAction: pokemon_card_id -> pokemon_id
- SelectActiveAction: card_id -> pokemon_id
- record_ability_use() -> ability_uses_this_turn += 1
Added 26 new tests covering:
- Energy deck setup (Pokemon Pocket style)
- Prize card mode
- Deck size validation (too large)
- PlayPokemonAction (to active, to bench, not found)
- EvolvePokemonAction (success, not in hand, target not found)
- PlayTrainerAction (item, supporter, stadium, replacement)
- UseAbilityAction (success, not found, invalid index)
- SelectActiveAction (forced action, not on bench)
- Deck-out on turn start
- Attack edge cases (no energy, invalid index)
- Retreat without bench
- Attach energy from energy zone
Test count: 711 -> 737 (+26)
Coverage: 89% -> 94% overall, engine.py 55% -> 81%