Add centralized deal_damage() method to GameEngine that handles life
reduction, stat tracking, commander damage (both per-seat and per-card),
and elimination checks. Route both burn spells and combat damage through
this unified path, building on the dual-dict commander damage model
merged in PR #89.
- Add is_direct_damage / direct_damage_amount fields to Card
- Add burn spell detection via known-card table + oracle regex fallback
- Route burn spells in _play_spells() through deal_damage()
- Refactor _resolve_combat() to route per-attacker damage through deal_damage()
- Add 38 regression tests covering deal_damage(), burn detection, spell routing,
combat routing, and full-game integration
Co-authored-by: Claude Code <noreply@anthropic.com>