Feat: Add support for custom success exit codes

Refactors the process invocation logic to use the .NET Process class for more robust output stream handling and to avoid temporary files.

Introduces a feature allowing users to specify additional success exit codes for applications in the UI. These codes are now considered successful during the installation process.

Adds a 'PAUSE' command to halt script execution and wait for user input.

FFUDevelopment/BuildFFUVM_UI.xaml

@@ -373,6 +373,10 @@
                                     <Button x:Name="btnBrowseAppSource" Grid.Column="1" Content="Browse..." Width="80" Margin="5,0,0,0" VerticalAlignment="Center"/>
                                 </Grid>
 
+                                <!-- Additional Exit Codes -->
+                                <TextBlock Text="Additional Exit Codes:" Margin="0,0,0,5"/>
+                                <TextBox x:Name="txtAppAdditionalExitCodes" Margin="0,0,0,10" ToolTip="Enter a comma-separated list of additional success exit codes."/>
+
                                 <!-- Add Application Button -->
                                 <Button x:Name="btnAddApplication" Content="Add Application" Width="120" HorizontalAlignment="Left" Margin="0,10,0,10" Padding="10,5" ToolTip="Add the application to the list"/>
 
@@ -392,6 +396,7 @@
                                                 <GridViewColumn Header="Command Line" DisplayMemberBinding="{Binding CommandLine}" Width="200"/>
                                                 <GridViewColumn Header="Arguments" DisplayMemberBinding="{Binding Arguments}" Width="200"/>
                                                 <GridViewColumn Header="Source" DisplayMemberBinding="{Binding Source}" Width="150"/>
+                                                <GridViewColumn Header="Exit Codes" DisplayMemberBinding="{Binding AdditionalExitCodes}" Width="100"/>
                                                 <GridViewColumn Header="Copy Status" DisplayMemberBinding="{Binding CopyStatus}" Width="150"/>
                                                 <GridViewColumn Header="Action" Width="85">
                                                     <GridViewColumn.CellTemplate>