Improve Reverb Damping Over Distance and Through Obstacles

Make gunshot reverb respond dynamically to distance, surrounding geometry, and the number of obstacles between the sound and the listener. Nearby shots could retain a sharper and brighter reverb, while distant or obstructed shots should sound progressively darker and more muffled as walls, corners, and other surfaces absorb their higher frequencies. Reverb tails could also gradually lose high-frequency detail as they decay instead of maintaining the same bright character until they end. This would improve spatial realism and leave more room in the audio mix for other important sounds.