docs: update handoff after PR 42 merge

docs/HANDOFF.md

@@ -2,7 +2,7 @@
 
 Current state of the project and active work. Read this at session start. Update before compaction or at natural breakpoints.
 
-**Last updated:** 2026-06-02
+**Last updated:** 2026-06-03
 
 ## Project State
 
@@ -60,6 +60,7 @@ Triage pattern: fix P1/P2 with code, create TODOs for P3/nitpicks, reply to ever
 
 ## Recent Context
 
+- 2026-06-03 PR #42 (`feat: add brainstorm panel review pack`) merged through the merge queue after follow-up fixes. Added `refinery review-brainstorm-panels`, recorded Pi-backed L2 benchmark results and first-pass panel review docs, and kept `score-only` as the recommended default. Review feedback addressed: bare `--key-path` filenames no longer call `create_dir_all("")`; `--strategies` and artifact metadata now parse through `BrainstormIterationStrategy`; saved `propose-*.md` text is preserved verbatim in review packs; handoff timestamp refreshed. Final checks observed before merge: GitHub Actions Build/Check/Test passed, Buildkite build #36 passed, and CodeRabbit passed. Local verification included `cargo fmt --all`, `cargo test -p refinery_cli review_brainstorm_panels`, `cargo clippy -p refinery_cli --all-targets -- -D warnings`, `cargo build --workspace`, and `cargo test --workspace`.
 - 2026-06-01 first-pass brainstorm L2 panel review completed (`todos/013`, `docs/brainstorms/2026-06-01-brainstorm-l2-panel-review.md`): reviewed the blind pack at `target/brainstorm-benchmark-2026-05-29-l2-pi-serial/logs/l2-panel-review-pack.md` and unblinded with `l2-panel-review-key.json`. Qualitative result: `score-only` looked strongest on useful diversity/non-overlap, `full-visibility` strongest on actionability/coverage, and `own-reviews` did not dominate globally but produced the strongest debugging/process panel. Recommendation remains: keep production default `score-only`; do not promote `full-visibility` despite higher automated quality scores until stronger human/calibrated judge evidence exists. For L3 prompt-reframing, use `score-only` as baseline and include `own-reviews` only if budget allows.
 - 2026-05-30 brainstorm L2 iteration strategy benchmark completed (`todos/013`, `docs/brainstorms/2026-05-30-brainstorm-l2-iteration-strategy-benchmark.md`): ran 24 clean Pi-backed runs (6 prompts × `blind`, `score-only`, `own-reviews`, `full-visibility`) with `pi/openai-codex/gpt-5.4:off`, `pi/zai/glm-5.1:off`, `pi/kimi-coding/kimi-k2-thinking:off`, and `pi/minimax/MiniMax-M2.7:off`. Used `--max-concurrent 1` to avoid Pi local config lock contention and raised bounded stdout capture from 1MB to 64MB because Pi JSON event streams can exceed 1MB. Analyzer outputs live under `target/brainstorm-benchmark-2026-05-29-l2-pi-serial/logs/` (`run-dirs-clean.txt`, `l2-analysis-clean.json`, `l2-analysis-clean.txt`). Current `controversy_floor_7` aggregate: `full-visibility` highest quality (`mean=8.204`, `min=7.944`) but highest lexical overlap (`0.132`); `score-only` lowest lexical overlap (`0.097`) but lower quality (`mean=7.889`); `own-reviews` middle-ground (`mean=8.019`, disagreement `0.517`). Added `refinery review-brainstorm-panels` and generated blind review artifacts for `score-only`, `own-reviews`, and `full-visibility`: `l2-panel-review-pack.md` plus `l2-panel-review-key.json` in the same logs dir. Recommendation: keep production default `score-only` until whole-panel diversity/human or calibrated model-judge review checks semantic convergence and best-answer regret. Verified with `cargo fmt --all -- --check`, `cargo test -p refinery_cli review_brainstorm_panels`, `cargo clippy -p refinery_cli --all-targets -- -D warnings`, `cargo test -p tundish_providers`, and `cargo clippy -p tundish_providers --all-targets -- -D warnings`.
 - 2026-05-31 PR #40 (`feat: add Pi provider and brainstorm benchmark variants`) passed final review/checks after follow-up commits. Addressed CodeRabbit/GHA feedback with nested `pi`/`opencode` model-spec validation, plan review-date refresh, and Clippy sort lint fixes; addressed Gemini feedback by comparing `ModelId` directly where compatible, accepting string evaluation scores, and preserving `USERPROFILE`; addressed Codex feedback by forwarding a whitelist of Pi credential/config env vars after `env_clear`. Final observed checks before merge: GitHub Actions Build/Check/Test passed, Buildkite build #31 passed, CodeRabbit approved. Local verification included `cargo fmt --all -- --check`, `cargo clippy --workspace -- -D warnings`, `cargo clippy --workspace --all-targets -- -D warnings`, `cargo build --workspace`, and `cargo test --workspace`.