fix(lights, render): restore authentic material dimming and smooth directional corona transition

[CanerKaraca23]

Summary

• Off-State Material Surface Properties & Color Dimming: Restores authentic AVS-style material dimming during inertia fade-in and fade-out. Instead of dimming towards pitch black (0.0f ambient / (0, 0, 0) color), GetLightSurfaceProps smoothly interpolates ambient, diffuse, and specular between the model's original off-state properties (origProps) and the glowing state (ms_LightSurfaceProps).
• Frame Step Jitter Elimination: Ensures fLightFactor in manager.cpp steps strictly once per vehicle frame using !data.bLightRenderedThisFrame[type] to prevent multiple components from advancing the factor multiple times in the same frame.
• Directional Corona Cosine Falloff: Applies a physical cosine falloff in RegisterCoronaDirectional across the light beam cone (angleFromCenter), producing natural, smooth sweep transitions when rotating beacons/rotators turn towards and away from the camera.