Provide a merge tool for themed files

[MaxKless]

Is your feature request related to a problem? If yes, please describe it.

If you customize a component with the new theme-specifc overrides feature, you essentially decouple it from the regular development process. Newly released changes to the PWA will not be propagated into your customizations and to consume the changes you have to manually copy/rewrite/merge the files.

Describe the desired solution.

It would be great if the PWA were to provide a tool that makes this job easier for you. Functionality could include:

• Showing a list of changes to overriden files between your current and desired version
• Show git diffs between your overriden files and the desired base files
• Guide you through merging or skipping changes

Maybe this could be a VSCode extension for easy visual support.

Describe alternatives you've considered.

Manually merging files or rewriting customized logic on changed files.

AB#71522