When copy-pasting components, assets/files appear to be duplicates

When you paste a component into a course multiple times, each of its files gets copied into the course's "Files & Uploads" with a unique prefix of components/{type}/{original_id}/{filename} (see _import_file_into_course and build_components_import_path which is weirdly in the video code). This gets transformed to components_{type}_{original_id}_{filename}, but only the file name part is visible in the files list, so it looks like there's a lot of duplicates:

Suggested fix: if a static asset is in a subfolder, the subfolder path should be displayed in grey text above the actual filename.

Annoying problem: There is absolutely nothing in the API that indicates the difference between an asset in a subfolder and an asset with underscores in its name, other than the fact that the display_name is much shorted than the full filename part of the various URLs. What's more, if you have an asset like components/problem/problem5da54866/simple-question.js (which has URLs that end in components_problem_problem5da54866_simple-question.js) and you deliberately upload an asset with the same name as the URL part (components_problem_problem5da54866_simple-question.js), you will now see two assets in the list, but they will both have the same URLs and same filename (the display_name of the existing asset will change from simple-question.js to components_problem_problem5da54866_simple-question.js and a second components_problem_problem5da54866_simple-question.js will appear, both actually being the same file).

Start by tracing the Files & Uploads UI in frontend-app-authoring and compare its displayed names with the paths produced by _import_file_into_course in cms/djangoapps/contentstore/helpers.py and build_components_import_path in openedx/core/djangoapps/video_config/transcripts_utils.py. Done should show subfolder paths separately from filenames and make assets with indistinguishable displayed names understandable without changing their URLs.