Sprint system with stamina drain and recovery

Pattern: Variables bIsSprinting(bool), Stamina(float)=100, MaxStamina(float)=100, SprintSpeed(float)=1200, WalkSpeed(float)=600, DrainRate(float)=20, RecoverRate(float)=10. Sprint pressed: bIsSprinting=true → SetMaxWalkSpeed(SprintSpeed). Released: bIsSprinting=false → SetMaxWalkSpeed(WalkSpeed). Tick: Branch(bIsSprinting) → Stamina -= DrainRate*DT. Else: Stamina += RecoverRate*DT. Clamp(0, Max). If Stamina<=0 → force stop sprint.