chore(ai-env): gpt-6.1-sol for the comparison run (C-G1, C-I1, V-I1)

luna 캠페인에서 2층 진단이 발생한 3건을 sol로 재실행해 라벨·조치·비용·소요를 비교한다(설계서 11.1).

vm/ai-env/ai.env

@@ -6,7 +6,7 @@ DISCORD_ESCALATION_CHANNEL_ID=1557425282363691048
 # optional: restrict button decisions to one role id (empty = any member of the server)
 DISCORD_APPROVER_ROLE_ID=
 # experiment design 11.1: candidates gpt-6-astra / gpt-6.1-sol / gpt-6-luna (OpenAI model page 2026-10-08). luna for the first live checks and campaign (budget), compare with sol afterwards
-OPENAI_MODEL=gpt-6-luna
+OPENAI_MODEL=gpt-6.1-sol
 EMBED_MODEL=text-embedding-3-small
 HARNESS_URL=http://10.20.0.11:8080
 MIMIR_URL=http://10.20.0.10:9009/prometheus