Display Resolved Variable Values in Change Template Preview

Change templates currently display variable placeholders in the Define Change and Execute nodes even after values have been assigned to those variables, requiring users to infer the actual configuration that will be pushed to the device. This enhancement would allow the template preview to substitute assigned variable values into the displayed configuration, showing the fully resolved text that will be sent to the device. This capability would help teams managing templates with many variables confirm the exact configuration prior to execution, reducing the risk of applying an incorrect or unintended change.