Default E2E model changed from Opus to Sonnet (5x faster, 5x cheaper).
Session runner now accepts `model` option with EVALS_MODEL env var override.
Added timing telemetry (first_response_ms, max_inter_turn_ms) and wall_clock_ms
to eval-store for diagnosing rate-limit impact. Added EVALS_FAST test filtering.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>