FurShell authoring: drop orphaned scale-influence prop, tune fur X-ray

FurShell.mat: remove the now-orphaned _FurScaleInfluence serialization.
Player.prefab: _xrayFurStrength tuned to ~0 (fur X-ray glow off).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Materials/FurShell.mat

@@ -37,7 +37,6 @@ Material:
     - _Density: 250
     - _DirRandomness: 0.3
     - _FurObjScale: 1
-    - _FurScaleInfluence: 0.5
     - _FurSoftness: 0.5
     - _FurThreshold: 0
     - _RimPower: 3

Assets/Prefabs/Player.prefab

@@ -574,6 +574,7 @@ MonoBehaviour:
   _windSpeed: 2
   _windFrequency: 4
   _windDirection: {x: 0.5, y: 0.7}
+  _xrayFurStrength: 0.00001
   _shadowMode: 0
   _receiveShadows: 1
   _hideSourceRenderer: 1