inspect: split trail output into individual findings

When a review profile posts to a trail, do not trust the judge prompt to produce API-ready structure. Split multi-bullet verdicts into separate whole-change findings before posting, preserving continuation/nested lines under each bullet. Single verdicts keep the old one-finding behavior.

Post split findings through one trail review session using comment batches, and strengthen the judge prompt to ask for one issue per bullet. This guards custom prompts too because splitting happens at the trail-output boundary.