Remove CanvasState delegating methods from Canvas

Removed delegating methods to CanvasState from Canvas.js and updated all references to use canvas.canvasState directly for state operations (undo, redo, saveStateToDB). Updated CanvasInteractions.js, CanvasIO.js, CanvasLayers.js, and CanvasView.js accordingly. Updated REFACTORING_GUIDE.md to reflect the completion of this refactor.

js/Canvas.js

@@ -469,11 +469,11 @@ export class Canvas {
      * - this.canvasInteractions dla obsługi interakcji
      * - this.canvasIO dla operacji I/O
      * - this.canvasState dla zarządzania stanem
+     * 
+     * UWAGA: Metody delegujące do CanvasState zostały usunięte.
+     * Używaj: canvas.canvasState.saveStateToDB(), canvas.canvasState.undo(), etc.
      */
     
-    // Delegacje do CanvasState
-    async saveStateToDB(immediate = false) { return this.canvasState.saveStateToDB(immediate); }
-    
     // Delegacje do CanvasLayers  
     async copySelectedLayers() { return this.canvasLayers.copySelectedLayers(); }
     async handlePaste(addMode) { return this.canvasLayers.handlePaste(addMode); }