Freeze players during map load: kill gravity and hide own mesh

- PlayerCharacterController: GravityEnabled toggle. When off, hold
  vertical velocity at zero and skip steep-slope sliding so a frozen
  avatar neither falls nor drifts; true is byte-for-byte the old path.
- GameModeManager: during Loading, additionally disable gravity and
  hide the local body (SkinnedMesh + fur shell), re-asserted each frame
  to catch the mid-load lobby->match respawn. Restored (body shown,
  gravity on) before ActiveMode.Enter() on release to Hide.
- MatchManager: enter Loading *before* SwapScenes so still-bound lobby
  avatars are frozen before their floor unloads. Fixes the player
  falling into the void during the lobby->map scene swap.

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

Assets/Scripts/Components/Controller/PlayerCharacterController.cs

@@ -151,6 +151,14 @@ public class PlayerCharacterController : MonoBehaviour
     /// </summary>
     public bool ControlEnabled { get; set; } = true;
 
+    /// <summary>
+    /// When false, gravity, ground-stick and slope-sliding are suspended and the vertical velocity is
+    /// held at rest, so the avatar hovers at its spawn position instead of settling. Set by the
+    /// GameModeManager during the pre-Hide loading barrier (alongside <see cref="ControlEnabled"/>) and
+    /// restored when the Hide phase begins.
+    /// </summary>
+    public bool GravityEnabled { get; set; } = true;
+
     /// <summary>
     /// When set, the body faces this world-space yaw (degrees) every frame instead of turning toward its
     /// movement direction. First-person sets it so the character always faces where the camera looks;
@@ -418,20 +426,30 @@ public class PlayerCharacterController : MonoBehaviour
         // (also covers balancing on a sharp box edge).
         float slopeAngle = Vector3.Angle(_groundNormal, Vector3.up);
         bool onSteepSlope = slideDownSteepSlopes
+            && GravityEnabled
             && _controller.isGrounded
             && slopeAngle > _controller.slopeLimit + 0.01f;
 
-        if (_controller.isGrounded)
+        if (!GravityEnabled)
         {
-            if (_verticalVelocity < 0f)
-                _verticalVelocity = groundedStickVelocity;
-
-            // No jumping off a slope too steep to stand on.
-            if (jumpPressed && !onSteepSlope)
-                _verticalVelocity = Mathf.Sqrt(jumpHeight * -2f * gravity);
+            // Loading barrier freeze: no gravity or ground-stick, hold vertical velocity at rest so the
+            // avatar keeps its spawn position (movement input is already cut via ControlEnabled).
+            _verticalVelocity = 0f;
         }
+        else
+        {
+            if (_controller.isGrounded)
+            {
+                if (_verticalVelocity < 0f)
+                    _verticalVelocity = groundedStickVelocity;
 
-        _verticalVelocity += gravity * Time.deltaTime;
+                // No jumping off a slope too steep to stand on.
+                if (jumpPressed && !onSteepSlope)
+                    _verticalVelocity = Mathf.Sqrt(jumpHeight * -2f * gravity);
+            }
+
+            _verticalVelocity += gravity * Time.deltaTime;
+        }
 
         Vector3 slideVelocity = Vector3.zero;
         if (onSteepSlope)