Implements 09-01-PLAN.md (BOT-03 reverse-proxy tracer) end-to-end in the
botfight repo (pushed to origin main): server/src/middleware/arena-proxy.ts,
its 9-test end-to-end suite, app.ts mount, fights.ts SSE fix, docker-compose.yml
env-var docs. Records the T-09-02 threat-model correction (plain HTTP is a
supported upstream scheme, not https-only, per user decision) and a
pre-existing migrate.ts/schema.ts drift found out-of-scope during
verification.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
