fix: Add cancellation handling for writing process

- Implemented cancellation signal connection in main.cpp to notify the QML window.
- Added onCancelled function in main.qml to forward cancellation events to the wizard container.
- Introduced onWriteCancelled function in WizardContainer.qml to reset writing state and navigate back to the writing step.
- Updated WritingStep.qml to ensure proper identification of the writing step for state management.

Author: tdewey-rpi

src/main.cpp

@@ -441,6 +441,7 @@ int main(int argc, char *argv[])
     qmlwindow->connect(&imageWriter, SIGNAL(preparationStatusUpdate(QVariant)), qmlwindow, SLOT(onPreparationStatusUpdate(QVariant)));
     qmlwindow->connect(&imageWriter, SIGNAL(error(QVariant)), qmlwindow, SLOT(onError(QVariant)));
     qmlwindow->connect(&imageWriter, SIGNAL(finalizing()), qmlwindow, SLOT(onFinalizing()));
+    qmlwindow->connect(&imageWriter, SIGNAL(cancelled()), qmlwindow, SLOT(onCancelled()));
     // osListPrepared is handled by wizard OSSelection instead of main window
     qmlwindow->connect(&imageWriter, SIGNAL(networkInfo(QVariant)), qmlwindow, SLOT(onNetworkInfo(QVariant)));
     qmlwindow->connect(&imageWriter, SIGNAL(selectedDeviceRemoved()), qmlwindow, SLOT(onSelectedDeviceRemoved()));

src/main.qml

@@ -348,6 +348,13 @@ ApplicationWindow {
         wizardContainer.onFinalizing();
     }
 
+    function onCancelled() {
+        // Forward to wizard container to handle write cancellation
+        if (wizardContainer) {
+            wizardContainer.onWriteCancelled();
+        }
+    }
+
     function onNetworkInfo(msg) {
         if (imageWriter.isEmbeddedMode() && wizardContainer) {
             wizardContainer.networkInfoText = msg;

src/wizard/WizardContainer.qml

@@ -1099,6 +1099,24 @@ Item {
         }
     }
 
+    function onWriteCancelled() {
+        // Reset write state
+        isWriting = false
+        
+        // Navigate back to writing step (which will show the summary since isWriting is false)
+        if (currentStep !== stepWriting) {
+            jumpToStep(stepWriting)
+        }
+        
+        // Reset the writing step's state if it exists
+        if (wizardStack.currentItem && wizardStack.currentItem.objectName === "writingStep") {
+            wizardStack.currentItem.isWriting = false
+            wizardStack.currentItem.cancelPending = false
+            wizardStack.currentItem.isFinalising = false
+            wizardStack.currentItem.isComplete = false
+        }
+    }
+    
     function onDownloadProgress(now, total) {
         // Forward to the WritingStep if currently active
         if (currentStep === stepWriting && wizardStack.currentItem) {

src/wizard/WritingStep.qml

@@ -13,6 +13,7 @@ import ImageOptions
 
 WizardStepBase {
     id: root
+    objectName: "writingStep"
 
     required property ImageWriter imageWriter
     required property var wizardContainer