NewCursorFromFlags validated --first/--last, --after/--before, and --after/--last as mutually exclusive, but missing the symmetric --first/--before guard. Passing --first with --before fell into the backward branch, where size defaulted from the unset --last and the direction silently flipped to Tail, discarding --first and reversing pagination. Reject the combination up front like the other invalid pairings. Signed-off-by: Émile Ré <emile@probo.com>