[ccacciari]

FsspecStore._ls builds its file entries from list_with_delimiter_async, whose ObjectMeta already carries last_modified and version, but keeps only name, size, type and e_tag. So fs.ls(path, detail=True) gives no modification time, while fs.info(path) on the same file gives last_modified and version from its HEAD request.

The two disagree in practice:

• ls(detail=True) users (file browsers, sync tools) see no date for any object, and fsspec's generic modified() cannot be answered from a listing.
• _info answers from the directory cache when the parent was listed, so whether info() returns last_modified depends on whether the parent was listed first.

This adds both fields to each file entry, so a listed entry has the same fields info() returns. It needs no extra request, since the values are already in the listing response. The timestamps differ only in precision: a listing reports milliseconds, while HEAD's Last-Modified header has whole seconds. Directory entries (common prefixes) are unchanged: they have no metadata of their own.

The new test lists a file, clears the cache so info() goes to the store, and checks that the two agree on version and on last_modified to within a second.