Add Weapon-Holding Fatigue with Stamina

Add a fatigue system that affects the player when aiming down sights for an extended period. Weapon sway could gradually increase as the operator’s arms become tired, making it more difficult to maintain a perfectly steady aim. Heavier weapons could cause fatigue more quickly, while lowering the weapon or leaving ADS would allow the operator to recover. Fatigue could also slightly reduce recoil control during sustained automatic fire, encouraging players to use shorter and more controlled bursts.