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/GameModeManager.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using UnityEngine;
+using Unity.Cinemachine;
 #if ENABLE_INPUT_SYSTEM
 using UnityEngine.InputSystem;
 #endif
@@ -108,6 +109,41 @@ public class GameModeManager : MonoBehaviour
             m.Bind(this);
     }
 
+    /// <summary>
+    /// Binds the scene singletons (this manager, the orbit/first-person cameras, the painter) to the
+    /// locally-owned networked player after it spawns, then enters Player Control. Called from
+    /// <see cref="NetworkPlayerSetup"/> on the owning client. Before this runs the scene has no player,
+    /// so the cycle sits in a player-less mode (Paint); this promotes it once the avatar exists.
+    /// </summary>
+    public void BindLocalPlayer(PlayerCharacterController localPlayer)
+    {
+        if (!localPlayer) return;
+        player = localPlayer;
+
+        // The painter lives on the player (per-avatar), so bind the local one.
+        if (!painter) painter = localPlayer.GetComponentInChildren<MeshPainter>(true);
+
+        Transform camTarget = localPlayer.transform.Find("CameraTarget");
+
+        // Re-point the third-person orbit camera (Cinemachine Follow/LookAt) at the local avatar.
+        if (cameraInput)
+        {
+            var vcam = cameraInput.GetComponent<CinemachineCamera>();
+            if (vcam) { vcam.Follow = camTarget; vcam.LookAt = camTarget; }
+        }
+
+        if (firstPerson)
+            firstPerson.SetPlayer(localPlayer);
+
+        // Tear down the pre-spawn (player-less) mode and rebuild with Player Control available.
+        ActiveMode?.Exit();
+        _activeIndex = -1;
+        BuildModes();
+
+        int idx = _modes.FindIndex(m => m is PlayerControlMode);
+        SwitchTo(idx >= 0 ? idx : Mathf.Clamp(startModeIndex, 0, _modes.Count - 1));
+    }
+
     private void Update()
     {
         if (_modes.Count == 0) return;