refactor: clean up ImageNode code structure and improve readability

src/blog/nodes/ImageNode.tsx

@@ -49,8 +49,7 @@ export type SerializedImageNode = Spread<
     maxWidth: number;
     width?: number;
     fileKey?: string;
-    uploadProgress?: number;
+    // uploadProgress and uploadError are runtime-only, not serialized
-    uploadError?: string;
   },
   SerializedLexicalNode
 >;
@@ -84,7 +83,7 @@ export class ImageNode extends DecoratorNode<JSX.Element> {
   }
 
   static importJSON(serializedNode: SerializedImageNode): ImageNode {
-    const { altText, height, width, maxWidth, fileKey, uploadProgress, uploadError } = serializedNode;
+    const { altText, height, width, maxWidth, fileKey } = serializedNode;
     
     // Generate src from fileKey if available, otherwise use empty string
     const src = fileKey ? '' : ''; // src will be generated from fileKey when rendering
@@ -96,8 +95,7 @@ export class ImageNode extends DecoratorNode<JSX.Element> {
       src,
       width,
       fileKey,
-      uploadProgress,
+      // uploadProgress and uploadError are not imported - they're runtime-only
-      uploadError,
     });
   }
 
@@ -158,8 +156,7 @@ export class ImageNode extends DecoratorNode<JSX.Element> {
       version: 1,
       width: this.__width === 'inherit' ? 0 : this.__width,
       fileKey: this.__fileKey,
-      uploadProgress: this.__uploadProgress,
+      // Don't export uploadProgress or uploadError - they're runtime-only UI state
-      uploadError: this.__uploadError,
     };
   }