Rename app to SIAB Scale and update test suite

lib/screens/timbang_screen.dart

@@ -58,8 +58,8 @@ class TimbangScreen extends StatelessWidget {
                           builder: (context, snapshot) {
                             final label = snapshot.data?.trim() ?? '';
                             final title = isConnected && label.isNotEmpty
-                                ? 'TIMBANGAN $label SIAB'
-                                : 'TIMBANGAN SIAB';
+                                ? 'SIAB SCALE - $label'
+                                : 'SIAB SCALE';
 
                             return _HeaderSection(
                               title: title,