Add NGO networking with owner-authoritative player position sync

Install Netcode for GameObjects 2.13.0 + Unity Transport 2.6.0 and wire up
the first networking milestone: syncing player position/rotation across clients.

- NetworkBootstrap: Host/Client/Server controls (OnGUI + H/C hotkeys) for
  local clone testing over loopback 127.0.0.1:7777.
- NetworkPlayerSetup: per-avatar owner gating. The local owner binds the
  GameModeManager and cameras to itself; remote avatars disable their
  controller/CharacterController and receive transform via NetworkTransform.
- GameModeManager.BindLocalPlayer: central runtime rebind to the locally
  spawned player.
- FirstPersonController.SetPlayer: explicit runtime rebind hook.
- Player prefab: NetworkObject + NetworkTransform (owner-authoritative,
  position + rotation) + NetworkPlayerSetup; registered as PlayerPrefab.
- Scene: NetworkManager + UnityTransport added; the fixed scene player
  instance removed in favor of spawn-on-connect.

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

Assets/Scripts/FirstPersonController.cs

@@ -175,6 +175,22 @@ public class FirstPersonController : MonoBehaviour
             if (r) r.enabled = !hidden;
     }
 
+    /// <summary>
+    /// Explicitly binds this rig to the locally-owned networked player (overriding the scene-wide
+    /// auto-resolve, which could otherwise latch onto a remote avatar). Called by the GameModeManager
+    /// when the local player spawns.
+    /// </summary>
+    public void SetPlayer(PlayerCharacterController p)
+    {
+        if (!p) return;
+        _player = p;
+        _poseController = p.GetComponent<PlayerPoseController>();
+        Transform t = p.transform.Find("CameraTarget");
+        if (t) cameraTarget = t;
+        hiddenRenderers = p.GetComponentsInChildren<SkinnedMeshRenderer>(true);
+        _resolved = true;
+    }
+
     void ResolveReferences()
     {
         if (_resolved) return;