feat(ui): Implement reorder mode for shopping lists

Extends the reorder mode functionality to the main shopping lists screen.

- A long press on a shopping list card now activates reorder mode.
- In this mode, drag handles are shown on both the left and right sides of each card to support left- and right-handed use.
- Other actions (edit, delete, navigation) are disabled while in reorder mode.
- Navigating away from the screen via the drawer correctly disables the reorder mode.

app/src/main/java/de/lxtools/noteshop/MainActivity.kt

@@ -156,6 +156,7 @@ fun AppShell(
                         label = { Text(stringResource(id = screen.titleRes)) },
                         selected = screen == currentScreen,
                         onClick = {
+                            shoppingListsViewModel.disableReorderMode()
                             currentScreen = screen
                             selectedListId = null
                             scope.launch { drawerState.close() }

app/src/main/java/de/lxtools/noteshop/ui/shopping/ShoppingListsScreen.kt

@@ -5,6 +5,7 @@ import androidx.compose.animation.core.animateDpAsState
 import androidx.compose.animation.core.animateFloatAsState
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -66,6 +67,7 @@ fun ShoppingListsScreen(
     onEditList: (ShoppingListWithItems) -> Unit
 ) {
     val uiState by viewModel.uiState.collectAsState()
+    val isReorderMode by viewModel.isReorderMode.collectAsState()
     val coroutineScope = rememberCoroutineScope()
 
     Column(
@@ -91,10 +93,17 @@ fun ShoppingListsScreen(
                                     viewModel.deleteList(it.shoppingList)
                                 }
                             },
-                            modifier = Modifier
-                                .clickable { onListClick(listWithItems.shoppingList.id) },
+                            modifier = Modifier.pointerInput(isReorderMode) {
+                                if (!isReorderMode) {
+                                    detectTapGestures(
+                                        onLongPress = { viewModel.enableReorderMode() },
+                                        onTap = { onListClick(listWithItems.shoppingList.id) }
+                                    )
+                                }
+                            },
                             scope = this,
-                            isDragging = isDragging
+                            isDragging = isDragging,
+                            isReorderMode = isReorderMode
                         )
                     }
                 }
@@ -112,16 +121,14 @@ fun ShoppingListCard(
     onDeleteList: (ShoppingListWithItems) -> Unit,
     modifier: Modifier = Modifier,
     scope: ReorderableCollectionItemScope,
-    isDragging: Boolean
+    isDragging: Boolean,
+    isReorderMode: Boolean
 ) {
-    val elevation = animateDpAsState(if (isDragging) 0.dp else 0.dp, label = "elevation")
+    val elevation = animateDpAsState(if (isDragging) 4.dp else 1.dp, label = "elevation")
     val scale = animateFloatAsState(if (isDragging) 1.05f else 1.0f, label = "scale")
-    val backgroundColor = animateColorAsState(
-        if (isDragging) MaterialTheme.colorScheme.primaryContainer.copy(alpha = 0.7f)
-        else Color.Transparent, label = "backgroundColor"
-    )
+
     Card(
-        modifier = with(scope) { modifier.draggableHandle() }
+        modifier = modifier
             .fillMaxWidth()
             .padding(vertical = 4.dp, horizontal = 16.dp)
             .graphicsLayer {
@@ -129,7 +136,6 @@ fun ShoppingListCard(
                 scaleY = scale.value
             }
             .shadow(elevation.value)
-            .background(backgroundColor.value)
     ) {
         Column(modifier = Modifier.padding(16.dp)) {
             Row(
@@ -137,17 +143,27 @@ fun ShoppingListCard(
                 horizontalArrangement = Arrangement.SpaceBetween,
                 verticalAlignment = Alignment.CenterVertically
             ) {
+                if (isReorderMode) {
+                    IconButton(modifier = with(scope) { Modifier.draggableHandle() }, onClick = {}) {
+                        Icon(Icons.Rounded.DragHandle, contentDescription = "Reorder")
+                    }
+                }
                 Text(
                     text = listWithItems.shoppingList.name,
                     style = MaterialTheme.typography.titleMedium,
                     modifier = Modifier.weight(1f)
                 )
-                IconButton(onClick = { onEditList(listWithItems) }) {
+                IconButton(onClick = { onEditList(listWithItems) }, enabled = !isReorderMode) {
                     Icon(Icons.Default.Edit, contentDescription = stringResource(R.string.edit_list))
                 }
-                IconButton(onClick = { onDeleteList(listWithItems) }) {
+                IconButton(onClick = { onDeleteList(listWithItems) }, enabled = !isReorderMode) {
                     Icon(Icons.Default.Delete, contentDescription = stringResource(R.string.delete_list))
                 }
+                if (isReorderMode) {
+                    IconButton(modifier = with(scope) { Modifier.draggableHandle() }, onClick = {}) {
+                        Icon(Icons.Rounded.DragHandle, contentDescription = "Reorder")
+                    }
+                }
             }
         }
     }