The Forbidden non-author update/delete cases used user6, who also lacks access
to task 1, so they only proved access denial, not the author-only restriction.
Add cases driven by testuser1 against comment 4 on task 16 (project 7): user1
has write access via team 3 but did not author the comment (user6 did), so a
403 there genuinely exercises the authorship branch. Keep the user6 cases as
the no-access negatives, relabelled for clarity.
4d404e376a