Compare your lab work with fellow members

Skill Labs gained a compare-and-learn loop. When you submit a lab, you can choose to share your response with other members who take the same lab -- shown anonymously, so the comparison stays about the work, not the author.

Two deliberate rules: sharing is entirely opt-in (nothing you've done becomes visible unless you flip the toggle), and you can only browse others' responses after submitting your own attempt -- comparing comes after trying, not instead of it.

Also fixed: returning to a lab now resumes your latest attempt where you left off, instead of quietly starting you over. Retrying is still there -- as an explicit "start a fresh attempt" button.