refactor: isolate dictionary rows from mutation-block recomposition

Delete-block flag becomes a () -> Boolean provider read at state/gesture
time, so flipping it no longer recomposes the whole Dictionaries block.

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

@@ -28,6 +28,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
+import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clipToBounds
@@ -83,7 +84,7 @@ fun DictionaryListItem(
     onToggle: () -> Unit,
     onDelete: () -> Unit,
     modifier: Modifier = Modifier,
-    canDelete: Boolean = true
+    isDeleteBlocked: () -> Boolean = { false }
 ) {
     val haptic = LocalHapticFeedback.current
     val density = LocalDensity.current
@@ -95,8 +96,9 @@ fun DictionaryListItem(
     val offsetAnim = remember { Animatable(0f) }
 
     var rawOffset by remember { mutableFloatStateOf(0f) }
-    val isDeleteRevealed by remember(canDelete) {
-        derivedStateOf { canDelete && rawOffset <= -swipeThresholdPx }
+    val isDeleteBlockedCurrent by rememberUpdatedState(isDeleteBlocked)
+    val isDeleteRevealed by remember {
+        derivedStateOf { !isDeleteBlockedCurrent() && rawOffset <= -swipeThresholdPx }
     }
 
     LaunchedEffect(isDeleteRevealed) {
@@ -105,11 +107,14 @@ fun DictionaryListItem(
         }
     }
 
-    LaunchedEffect(canDelete) {
-        if (!canDelete) {
-            rawOffset = 0f
-            offsetAnim.snapTo(0f)
-        }
+    LaunchedEffect(Unit) {
+        snapshotFlow { isDeleteBlockedCurrent() }
+            .collect { blocked ->
+                if (blocked) {
+                    rawOffset = 0f
+                    scope.launch { offsetAnim.snapTo(0f) }
+                }
+            }
     }
 
     val currentOnDelete by rememberUpdatedState(onDelete)
@@ -142,13 +147,14 @@ fun DictionaryListItem(
                 .height(DictionaryItemHeight)
                 .background(MaterialTheme.colorScheme.surfaceVariant)
                 .graphicsLayer { translationX = offsetAnim.value }
-                .pointerInput(canDelete, maxSwipePx, swipeThresholdPx) {
-                    if (!canDelete) return@pointerInput
+                .pointerInput(maxSwipePx, swipeThresholdPx) {
                     detectHorizontalDragGestures(
                         onDragStart = {
+                            if (isDeleteBlockedCurrent()) return@detectHorizontalDragGestures
                             haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
                         },
                         onDragEnd = {
+                            if (isDeleteBlockedCurrent()) return@detectHorizontalDragGestures
                             val target = if (rawOffset <= -swipeThresholdPx) -maxSwipePx else 0f
                             rawOffset = target
                             scope.launch {
@@ -159,6 +165,7 @@ fun DictionaryListItem(
                             }
                         },
                         onDragCancel = {
+                            if (isDeleteBlockedCurrent()) return@detectHorizontalDragGestures
                             val target = if (rawOffset <= -swipeThresholdPx) -maxSwipePx else 0f
                             rawOffset = target
                             scope.launch {
@@ -169,6 +176,7 @@ fun DictionaryListItem(
                             }
                         },
                         onHorizontalDrag = { _, dragAmount ->
+                            if (isDeleteBlockedCurrent()) return@detectHorizontalDragGestures
                             val newOffset = (rawOffset + dragAmount).coerceIn(-maxSwipePx, 0f)
                             rawOffset = newOffset
                             scope.launch { offsetAnim.snapTo(newOffset) }

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

@@ -13,6 +13,7 @@ import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.hapticfeedback.HapticFeedbackType
@@ -75,6 +76,13 @@ fun DictionaryManagement(
         derivedStateOf { importState is ImportState.Importing || importState is ImportState.Extracting }
     }
     val hasEnabledSources by remember(sources) { derivedStateOf { sources.any { it.isEnabled } } }
+    val isBlockingMutations = isInProgress
+
+    // Invariant: the mutation-block flag is read only at state-read/gesture time (derivedStateOf,
+    // snapshotFlow, pointerInput callbacks), never at row composition time. A composition-time read
+    // (e.g. Modifier.alpha(if (isDeleteBlocked()) ...)) would invalidate every row on each flip.
+    val isMutationsBlockedState = rememberUpdatedState(isBlockingMutations)
+    val isDeleteBlocked = remember { { isMutationsBlockedState.value } }
 
     SectionCard(
         modifier = modifier
@@ -125,13 +133,13 @@ fun DictionaryManagement(
 
                     // Disable accessibility on background content during import to improve performance.
                     // The progress dialog remains accessible for cancellation.
-                    val backgroundModifier = if (isInProgress) {
+                    val backgroundModifier = if (isBlockingMutations) {
                         Modifier.semantics(mergeDescendants = true) { }
                     } else {
                         Modifier
                     }
 
-                    if (dictionaries.isEmpty() && !isInProgress) {
+                    if (dictionaries.isEmpty() && !isBlockingMutations) {
                         Column(
                             modifier = backgroundModifier
                                 .fillMaxWidth()
@@ -153,7 +161,7 @@ fun DictionaryManagement(
                             )
                         }
                     } else {
-                        if (dictionaryStatus is DictionaryStatus.NeedsUpdate && !isInProgress && hasEnabledSources) {
+                        if (dictionaryStatus is DictionaryStatus.NeedsUpdate && !isBlockingMutations && hasEnabledSources) {
                             DictionaryUpdateCard(
                                 onStartDownload = onStartDownload,
                                 modifier = backgroundModifier
@@ -167,10 +175,10 @@ fun DictionaryManagement(
                             modifier = Modifier
                                 .fillMaxWidth()
                                 .then(backgroundModifier),
-                            canDelete = !isInProgress
+                            isDeleteBlocked = isDeleteBlocked
                         )
 
-                        if (!isInProgress) {
+                        if (!isBlockingMutations) {
                             DictionaryActionButtons(
                                 onAddSource = {
                                     haptic.performHapticFeedback(HapticFeedbackType.TextHandleMove)
@@ -248,7 +256,7 @@ private fun DictionaryListSection(
     onToggleDictionary: (String) -> Unit,
     onDeleteDictionary: (Dictionary) -> Unit,
     modifier: Modifier = Modifier,
-    canDelete: Boolean = true
+    isDeleteBlocked: () -> Boolean = { false }
 ) {
     Column(
         modifier = modifier,
@@ -259,7 +267,7 @@ private fun DictionaryListSection(
                 dictionary = dictionary,
                 onToggle = { onToggleDictionary(dictionary.path) },
                 onDelete = { onDeleteDictionary(dictionary) },
-                canDelete = canDelete
+                isDeleteBlocked = isDeleteBlocked
             )
         }
     }