Refactor canvas and mask handling for clarity and maintainability

Removed redundant comments and streamlined logic across canvas-related modules, including mask positioning, garbage collection, and WebSocket communication. Improved code readability and maintainability by eliminating unnecessary explanations and clarifying intent in both Python and JavaScript files. No functional changes were made; this is a cleanup and refactor for better developer experience.

js/utils/CommonUtils.js

@@ -137,13 +137,11 @@ export function getStateSignature(layers) {
             blendMode: layer.blendMode || 'normal',
             opacity: layer.opacity !== undefined ? Math.round(layer.opacity * 100) / 100 : 1
         };
-        
-        // Include imageId if available
+
         if (layer.imageId) {
             sig.imageId = layer.imageId;
         }
-        
-        // Include image src as fallback identifier
+
         if (layer.image && layer.image.src) {
             sig.imageSrc = layer.image.src.substring(0, 100); // First 100 chars to avoid huge signatures
         }