Combat State System & Code Cleanup

Combat State System

• PlayerCombatState: New component tracking combat engagement status
• Stance Switch Blocking: Can't switch stance during combat timer (not just during attacks)
• Combat Timer: 3-second window after last attack before exiting combat

Codebase Review Refactoring

• Major cleanup: Removed unused code and dead paths
• Duplicate helpers extracted: Shared utilities consolidated
• Documentation fixes: Corrected outdated docs from audit findings