Fix INT: ContentSlider Slides editor wrote wrong prop key (image vs imageSrc)

MediaStylePanel's Slides array editor guarded on item.image !== undefined
and wrote `image` via AssetPicker's onChange, but ContentSlider (render
+ toHtml) reads slide.imageSrc. Default slides (imageSrc:'', no `image`
key) never showed an image picker at all, and any `image` value written
was a silent no-op on render/export.

Editor now guards/reads/writes `imageSrc` throughout, and the
"add slide" emptyItem matches defaultSlides' exact shape
(type/imageSrc/heading/text/bgColor).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/panels/right/styles/MediaStylePanel.tsx

@@ -145,14 +145,14 @@ export const MediaStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodePro
                     });
                   }} placeholder="Text" rows={2} style={{ ...smallInputStyle, resize: 'vertical' }} />
                 )}
-                {item.image !== undefined && (
+                {item.imageSrc !== undefined && (
                   <AssetPicker
                     variant="compact"
-                    value={item.image || ''}
+                    value={item.imageSrc || ''}
                     onChange={(url) => {
                       actions.setProp(selectedId, (props: any) => {
                         const updated = [...(props.slides || [])];
-                        updated[index] = { ...updated[index], image: url };
+                        updated[index] = { ...updated[index], imageSrc: url };
                         props.slides = updated;
                       });
                     }}
@@ -160,7 +160,7 @@ export const MediaStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodePro
                 )}
               </div>
             )}
-            emptyItem={{ heading: 'New Slide', text: '', image: '' }}
+            emptyItem={{ type: 'image', imageSrc: '', heading: 'New Slide', text: '', bgColor: '' }}
           />
         </CollapsibleSection>
       )}