fix(ui): remove cursor_renderer from gameplay group

CursorRenderer must always render on top — shouldn't have its z-index
managed by HudGroups. It's a world-space renderer, not a HUD element.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client/scripts/main.gd

@@ -73,7 +73,6 @@ func _ready() -> void:
 		news_ticker,
 		examine_display,
 		world_radial,
-		cursor_renderer,
 	]:
 		if node and node is CanvasItem:
 			HudGroups.register(node, "gameplay")