Scene authoring: ConversionStatue prefab, registration and wiring

- ConversionStatue.prefab: Hider variant stripped of player-only components
  (NetworkPlayerSetup, PlayerAnimationSync, ConcealmentMeter, PlayerScaler),
  controllers disabled, MatchStatue added.
- DefaultNetworkPrefabs.asset: register the statue prefab.
- Main.unity: wire MatchManager.statuePrefab.

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

Assets/DefaultNetworkPrefabs.asset

@@ -34,3 +34,8 @@ MonoBehaviour:
     SourcePrefabToOverride: {fileID: 0}
     SourceHashToOverride: 0
     OverridingTargetPrefab: {fileID: 0}
+  - Override: 0
+    Prefab: {fileID: 5508335275054701003, guid: 883d1d5c434f5a44884d1ef38a3a5db5, type: 3}
+    SourcePrefabToOverride: {fileID: 0}
+    SourceHashToOverride: 0
+    OverridingTargetPrefab: {fileID: 0}