fix: hide dictionary rows from accessibility while mutations blocked

invisibleToUser() removes blocked content from the accessibility tree;
mergeDescendants only regrouped traversal order.

app/src/main/java/com/example/research/ui/settings/components/DictionaryManagement.kt

@@ -23,6 +23,7 @@ import androidx.compose.ui.platform.LocalFocusManager
 import androidx.compose.ui.platform.LocalHapticFeedback
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.invisibleToUser
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
@@ -135,7 +136,7 @@ fun DictionaryManagement(
                     // Disable accessibility on background content during import to improve performance.
                     // The progress dialog remains accessible for cancellation.
                     val backgroundModifier = if (isBlockingMutations) {
-                        Modifier.semantics(mergeDescendants = true) { }
+                        Modifier.semantics { invisibleToUser() }
                     } else {
                         Modifier
                     }