feat: implement basic RPG mechanics with boss counter-attack

- Add Player and Boss data models (models.py)
- Implement command processing via regex matching (attack/heal/status)
- Add boss counter-attack mechanism (15 dmg per player attack)
- Add player death/respawn system (lose half gold, respawn full HP)
- Update frontend with boss HP bar, player stats panel, quick action buttons
- Add colored event log (red for attack, green for heal)
- Change port from 8000 to 8080

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/schemas.py

@@ -16,6 +16,13 @@ class EventType(str, Enum):
     TICK = "tick"
     SYSTEM = "system"
     ERROR = "error"
+    # RPG-specific events
+    ATTACK = "attack"
+    HEAL = "heal"
+    STATUS = "status"
+    BOSS_UPDATE = "boss_update"
+    BOSS_DEFEATED = "boss_defeated"
+    PLAYER_UPDATE = "player_update"
 
 
 class GameEvent(BaseModel):