Pivot to OnlyJevs: every match is a Trail

We bought onlyjevs.com. The scorer was never the product; the judge is. From now on a match is not a number we compute, it is a Trail: the couple's first change together, generated from their habits, opened on a branch, and judged by Jev the way Jev judges any diff.

Acceptance

• npm run match -- a b generates the couple's first change from their profiles, pushes match/<couple> from main and links it to a Trail.
• Only Jev runners are configured: Compatibility (Jev), Risk (Jev), Security (Jev), Slop (Jev). No sandbox, no agent session.
• The verdict is derived from those scores: compatibility, minus half the risk and security, minus a slop penalty.
• npm run eval reports how many labelled couples Jev's verdict puts in the expected band, honestly, pending included.
• The match card shows what Jev said before it shows why the app thought so.