[admin] possibility to switch between both patch + copy/paste versions

> I guess I partially agree with this, in particular for less experienced people it might be an advantage that they have to navigate to the files and within the files repeatedly -- they will probably learn better what is where. If one is used to looking at diffs it should be fine.
>
> For me both is fine, but my fingers feel rather twisted after typing `patch -p1 << 'EOF'` quite a bit :)
>
> The possibility to switch between both displays would be perfect IMO. Sometimes patching is also faster (if one runs out of time).

_Originally posted by @bernt-matthias in https://github.com/galaxyproject/training-material/issues/6515#issuecomment-3575190301_

Having patches that aren't patches, was an intentional didactic choice. This seems to have now been broken by GAT trainers https://github.com/galaxyproject/training-material/pull/6503

Start by reading the discussion in issue #6515 and the changes in pull request #6503 to understand the existing patch and copy/paste presentation. Define a switching mechanism that restores both display options while preserving the intended didactic behavior, then verify the affected training materials support both versions.

Written by the indexing model from the issue text.