Add error dialogs with retry/cancel for network failures

Implemented user-friendly error handling for network call failures:

Android (Compose):
- Created reusable ErrorDialog component with retry and cancel buttons
- Updated TasksScreen to show error dialog popup instead of inline error
- Error dialog appears when network calls fail with option to retry

iOS (SwiftUI):
- Created ErrorAlertModifier and ErrorAlertInfo helpers
- Added .errorAlert() view modifier for consistent error handling
- Updated TaskFormView to show error alerts with retry/cancel options
- Error alerts appear when task creation or other network calls fail

Both platforms now provide a consistent user experience when network
errors occur, giving users the choice to retry the operation or cancel.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

composeApp/src/commonMain/kotlin/com/example/mycrib/ui/components/ErrorDialog.kt

@@ -0,0 +1,65 @@
+package com.mycrib.android.ui.components
+
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.ButtonDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.graphics.Color
+
+/**
+ * Reusable error dialog component that shows network errors with retry/cancel options
+ *
+ * @param title Dialog title (default: "Network Error")
+ * @param message Error message to display
+ * @param onRetry Callback when user clicks Retry button
+ * @param onDismiss Callback when user clicks Cancel or dismisses dialog
+ * @param retryButtonText Text for retry button (default: "Try Again")
+ * @param dismissButtonText Text for dismiss button (default: "Cancel")
+ */
+@Composable
+fun ErrorDialog(
+    title: String = "Network Error",
+    message: String,
+    onRetry: () -> Unit,
+    onDismiss: () -> Unit,
+    retryButtonText: String = "Try Again",
+    dismissButtonText: String = "Cancel"
+) {
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = {
+            Text(
+                text = title,
+                style = MaterialTheme.typography.headlineSmall,
+                color = MaterialTheme.colorScheme.error
+            )
+        },
+        text = {
+            Text(
+                text = message,
+                style = MaterialTheme.typography.bodyMedium
+            )
+        },
+        confirmButton = {
+            Button(
+                onClick = {
+                    onDismiss()
+                    onRetry()
+                },
+                colors = ButtonDefaults.buttonColors(
+                    containerColor = MaterialTheme.colorScheme.primary
+                )
+            ) {
+                Text(retryButtonText)
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text(dismissButtonText)
+            }
+        }
+    )
+}

composeApp/src/commonMain/kotlin/com/example/mycrib/ui/screens/TasksScreen.kt

@@ -11,6 +11,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.mycrib.android.ui.components.CompleteTaskDialog
+import com.mycrib.android.ui.components.ErrorDialog
 import com.mycrib.android.ui.components.task.TaskCard
 import com.mycrib.android.ui.components.task.TaskPill
 import com.mycrib.android.ui.utils.getIconFromName
@@ -32,6 +33,16 @@ fun TasksScreen(
     var expandedColumns by remember { mutableStateOf(setOf<String>()) }
     var showCompleteDialog by remember { mutableStateOf(false) }
     var selectedTask by remember { mutableStateOf<com.mycrib.shared.models.TaskDetail?>(null) }
+    var showErrorDialog by remember { mutableStateOf(false) }
+    var errorMessage by remember { mutableStateOf("") }
+
+    // Show error dialog when tasks fail to load
+    LaunchedEffect(tasksState) {
+        if (tasksState is ApiResult.Error) {
+            errorMessage = (tasksState as ApiResult.Error).message
+            showErrorDialog = true
+        }
+    }
 
     LaunchedEffect(Unit) {
         viewModel.loadTasks()
@@ -64,7 +75,7 @@ fun TasksScreen(
         // No FAB on Tasks screen - tasks are added from within residences
     ) { paddingValues ->
         when (tasksState) {
-            is ApiResult.Idle, is ApiResult.Loading -> {
+            is ApiResult.Idle, is ApiResult.Loading, is ApiResult.Error -> {
                 Box(
                     modifier = Modifier
                         .fillMaxSize()
@@ -74,25 +85,6 @@ fun TasksScreen(
                     CircularProgressIndicator()
                 }
             }
-            is ApiResult.Error -> {
-                Box(
-                    modifier = Modifier
-                        .fillMaxSize()
-                        .padding(paddingValues),
-                    contentAlignment = androidx.compose.ui.Alignment.Center
-                ) {
-                    Column(horizontalAlignment = androidx.compose.ui.Alignment.CenterHorizontally) {
-                        Text(
-                            text = "Error: ${(tasksState as ApiResult.Error).message}",
-                            color = MaterialTheme.colorScheme.error
-                        )
-                        Spacer(modifier = Modifier.height(8.dp))
-                        Button(onClick = { viewModel.loadTasks() }) {
-                            Text("Retry")
-                        }
-                    }
-                }
-            }
             is ApiResult.Success -> {
                 val taskData = (tasksState as ApiResult.Success).data
                 val hasNoTasks = taskData.columns.all { it.tasks.isEmpty() }
@@ -276,4 +268,18 @@ fun TasksScreen(
             }
         )
     }
+
+    // Show error dialog when network call fails
+    if (showErrorDialog) {
+        ErrorDialog(
+            message = errorMessage,
+            onRetry = {
+                showErrorDialog = false
+                viewModel.loadTasks()
+            },
+            onDismiss = {
+                showErrorDialog = false
+            }
+        )
+    }
 }