Add Watermark

src/core/hud.ts

 import { Viewport } from './viewport';
 import { StatsPanel } from '../ui/stats-panel';
 import { FullscreenButton } from '../ui/fullscreen-button';
+import { Watermark } from '../ui/watermark';
 import { Nullable, Utils } from '../utils/utils';
 
 /** HUD container */
     /** Fullscreen button */
     #fullscreenButton: FullscreenButton;
 
+    /** Watermark */
+    #watermark: Watermark;
+
 
 
 
         // create internal components
         this.#statsPanel = new StatsPanel();
         this.#fullscreenButton = new FullscreenButton(viewport);
+        this.#watermark = new Watermark();
     }
 
     /**
         const parent = this._internalContainer;
         this.#statsPanel.init(parent, wantStatsPanel);
         this.#fullscreenButton.init(parent, wantFullscreenButton);
+        this.#watermark.init(parent);
 
         for(const element of parent.children as any as HTMLElement[]) {
             if(element.style.getPropertyValue('pointer-events') == '')
     {
         this._visible = false;
 
+        this.#watermark.release();
         this.#fullscreenButton.release();
         this.#statsPanel.release();