Fix PyQt6 compatibility issues in usb_creator_gui.py

- Fix Qt.AlignCenter -> Qt.AlignmentFlag.AlignCenter (line 227)
- Fix QLineEdit.Password -> QLineEdit.EchoMode.Password (password fields)
- Fix QMessageBox constants to use StandardButton enum
- Fix app.exec_() -> app.exec() for PyQt6 compatibility
- Resolves AttributeError issues on Windows with PyQt6

usb_creator_gui.py

@@ -224,7 +224,7 @@ class USBCreatorApp(QMainWindow):
         
         # Header
         header = QLabel("MBetter Live USB Creator")
-        header.setAlignment(Qt.AlignCenter)
+        header.setAlignment(Qt.AlignmentFlag.AlignCenter)
         header.setStyleSheet("font-size: 18px; font-weight: bold; margin: 10px;")
         layout.addWidget(header)
         
@@ -285,9 +285,9 @@ class USBCreatorApp(QMainWindow):
         layout = QFormLayout(group)
         
         self.password_input = QLineEdit()
-        self.password_input.setEchoMode(QLineEdit.Password)
+        self.password_input.setEchoMode(QLineEdit.EchoMode.Password)
         self.password_confirm = QLineEdit()
-        self.password_confirm.setEchoMode(QLineEdit.Password)
+        self.password_confirm.setEchoMode(QLineEdit.EchoMode.Password)
         
         layout.addRow("New Password:", self.password_input)
         layout.addRow("Confirm Password:", self.password_confirm)
@@ -535,9 +535,9 @@ class USBCreatorApp(QMainWindow):
         msg += "\nContinue?"
         
         reply = QMessageBox.question(self, "Confirm USB Creation", msg,
-                                   QMessageBox.Yes | QMessageBox.No)
+                                   QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No)
         
-        if reply == QMessageBox.Yes:
+        if reply == QMessageBox.StandardButton.Yes:
             # Disable UI and start worker thread
             self.create_button.setEnabled(False)
             self.progress_bar.setValue(0)
@@ -567,10 +567,10 @@ class USBCreatorApp(QMainWindow):
 
     def cancel_operation(self):
         if self.worker_thread and self.worker_thread.isRunning():
-            reply = QMessageBox.question(self, "Cancel Operation", 
+            reply = QMessageBox.question(self, "Cancel Operation",
                                        "Cancel the USB creation process?",
-                                       QMessageBox.Yes | QMessageBox.No)
-            if reply == QMessageBox.Yes:
+                                       QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No)
+            if reply == QMessageBox.StandardButton.Yes:
                 self.worker_thread.terminate()
                 self.create_button.setEnabled(True)
                 self.statusBar().showMessage("Operation cancelled")
@@ -594,7 +594,7 @@ def main():
     window = USBCreatorApp()
     window.show()
     
-    sys.exit(app.exec_())
+    sys.exit(app.exec())
 
 
 if __name__ == '__main__':