Enable third-person camera collision against BlockCam layer only

- Main: Deoccluder CollideAgainst = BlockCam (256), CameraRadius 0.01,
  HeroCutout.replaceDeoccluderPullIn off (re-enables AvoidObstacles at runtime)
- Lobby: Floor moved to BlockCam layer

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/Scenes/Main.unity

@@ -1234,7 +1234,7 @@ MonoBehaviour:
   m_EditorClassIdentifier: Unity.Cinemachine::Unity.Cinemachine.CinemachineDeoccluder
   CollideAgainst:
     serializedVersion: 2
-    m_Bits: 1
+    m_Bits: 256
   IgnoreTag: Player
   TransparentLayers:
     serializedVersion: 2
@@ -1244,7 +1244,7 @@ MonoBehaviour:
     Enabled: 1
     DistanceLimit: 0
     MinimumOcclusionTime: 0
-    CameraRadius: 0.07
+    CameraRadius: 0.01
     UseFollowTarget:
       Enabled: 0
       YOffset: 0
@@ -10224,7 +10224,7 @@ MonoBehaviour:
   m_EditorClassIdentifier: Assembly-CSharp::HeroCutout
   orbitInput: {fileID: 0}
   modes: {fileID: 0}
-  replaceDeoccluderPullIn: 1
+  replaceDeoccluderPullIn: 0
   radius: 0.9
   feather: 0.3
   depthFeather: 0.5