Replace panel tileKey with a direct color prop.

Drop theme panelTiles keys and the ArticleView update callback wiring.

src/components/article/boxes/ArticleViewName.jsx

@@ -239,6 +239,7 @@ export default class ArticleViewName extends Component {
         wide={3}
         minHeight={0}
         sx={headerTileSx}
+        color="#ffffff"
         value={value}
         onSave={this.handleSave}
         isDirty={draftDirty}