When changing the directory name, automatically change the corresponding package name in the dart code

In the current version, if you change the directory name, you need to manually change the dart code, which is very tedious

Start by tracing how the IntelliJ plugin handles directory renames and how it identifies the corresponding Dart package name. Confirm the expected behavior from the issue: changing a directory name should also update the related Dart code, then verify the behavior with the plugin's existing tests or rename workflow.

Written by the indexing model from the issue text.