feat: Implement core gameplay systems and data assets for health, stamina, stress, movement, hit reactions, and shield defense

Source/Framework/Private/Weapons/BPC_HitReactionSystem.cpp

@@ -0,0 +1,11 @@
+#include "Weapons/BPC_HitReactionSystem.h"
+
+UBPC_HitReactionSystem::UBPC_HitReactionSystem()
+{
+	PrimaryComponentTick.bCanEverTick = false;
+}
+
+void UBPC_HitReactionSystem::PlayHitReaction(float DamageAmount, FVector HitDirection, AActor* DamageCauser)
+{
+	// Stub — Blueprint child provides animation selection logic.
+}