Finalize switch from composerName to composer in Sheet model

lib/features/home/widgets/sheet_list_item.dart

@@ -21,7 +21,7 @@ class SheetListItem extends StatelessWidget {
   Widget build(BuildContext context) {
     return ListTile(
       title: Text(sheet.name),
-      subtitle: Text(sheet.composerName),
+      subtitle: Text(sheet.composer),
       onTap: onTap,
       onLongPress: onLongPress,
     );

lib/features/home/widgets/sheets_list.dart

@@ -80,7 +80,7 @@ class _SheetsListState extends State<SheetsList> {
     setState(() {
       _filteredSheets = widget.sheets.where((sheet) {
         final name = sheet.name.toLowerCase();
-        final composer = sheet.composerName.toLowerCase();
+        final composer = sheet.composer.toLowerCase();
 
         // Each term must appear in either name or composer
         return terms.every(
@@ -122,7 +122,7 @@ class _SheetsListState extends State<SheetsList> {
         ),
       );
     }
-    if (newComposer != sheet.composerName) {
+    if (newComposer != sheet.composer) {
       widget.syncService.queueChange(
         Change(
           type: ChangeType.composerNameChange,
@@ -135,7 +135,7 @@ class _SheetsListState extends State<SheetsList> {
     // Update local state
     setState(() {
       sheet.name = newName;
-      sheet.composerName = newComposer;
+      sheet.composer = newComposer;
     });
 
     // Update cached sheets