docs(oatp): formalize the +BSA PSu,inf deferral (data-blocked) after closing the auto-ECM xfail

docs/research/dead-ends.md

@@ -308,7 +308,7 @@ Artifacts: `data/enzymes/ugt_ivive_sf.json` (all-1.0 audited registry), `src/sis
 - **Hierarchical multi-assay target-denoising** — data fatal: of 5,338 unique CLint compounds **exactly 1** has cross-source measurements (field max ~50) → Dawid-Skene unidentifiable. Mechanism also wrong: Bowman & Benet 2019 (our own cited source) shows interlab variance is *systematic per-protocol bias*, not random noise — averaging averages bias.
 - **Calibrated-CLint-uncertainty → meta *routing*** — the inverse-variance mechanism already ran: DE-26 M7 Local-BMA **+0.082 worse**, M9 +0.014 worse. Only the *PI-recalibration* half survives (touches the interval, not the point estimate → cannot trip co-calibration), and only for *coverage/UQ*, not point-AAFE. CLint-CV ranks |Cmax fold-error| weakly (SRCC≈0.16).
 - **Per-subclass measured-input routing (aggregate)** — the ML track is `predict_cmax(smiles, dose)`, **structurally blind to measured ADME**, so the strongest meta track (3.01) is frozen and the shipped measured "≈11% gain" is *engine-only* and never propagates to the meta headline. Capability already shipped; the "targeted-selection" wrapper adds nothing testable.
-- **+BSA / albumin-mediated PSu,inf (OATP)** — *keep as correctness only, not a lever*: a real primary-literature mechanistic fix (Li/Benet 2020, ~1.9–2.0 fold, no scaling) but **inert** — touches 1 holdout drug (pravastatin, inviolable) and 0 prospective → ΔMeta≈0.000. Ships under correctness-over-benchmark (spec `2026-06-04-oatp-ecm-reanchor-design.md`).
+- **+BSA / albumin-mediated PSu,inf (OATP)** — *keep as correctness only, not a lever*: a real primary-literature mechanistic fix (Li/Benet 2020, ~1.9–2.0 fold, no scaling) but **inert** — touches 1 holdout drug (pravastatin, inviolable) and 0 prospective → ΔMeta≈0.000. Ships under correctness-over-benchmark (spec `2026-06-04-oatp-ecm-reanchor-design.md`). **Status 2026-07-06:** the abundance re-anchor (off holdout pravastatin → non-holdout pitavastatin) and the auto-ECM xfail closure shipped (statin FE-gates green, #103); the **+BSA PS reparameterization itself is formally DEFERRED as data-blocked** — the per-substrate PSu,inf(+BSA)/Kp values live only in the paywalled Li/Benet 2020 primary source (AAPS J; not to be fabricated), and even implemented it is near-zero-*observable* (the abundance re-anchors to pitavastatin, so only *relative* statin PS shifts; pravastatin stays validation-only) on top of headline-inert. Re-open only if the primary-source table becomes available.
 - **Structure→F as engine prior/anchor** — collides DE-28 (repo's own structure→F predictor = scaffold-CV R²=−0.09; the external "Q²=0.58" is the optimistic/AD-filtered tail) + DE-43 damping + circularity (engine E and structure→F are both functions of the same SMILES → no orthogonal information = DE-23 in F clothing).
 
 **Why the whole class fails (unifying):** CLint enters the pipeline **only through the engine track**, which the fixed-weight meta damps to ~18% pass-through (DE-43) under r>0.986 track co-calibration (DE-26). So any CLint improvement *in isolation* either re-learns the existing weights (null) or breaks co-calibration (regression) — the pattern of 18+ prior reverts. The floor is two floors (DE-14 target-noise + mechanistic transporter–enzyme-interplay IVIVE), neither reachable from the CLint side.

docs/research/experiment-log.md

@@ -10,6 +10,33 @@ Reverse-chronological. The project README carries only the **current** headline
 
 ---
 
+## 2026-07-06 — OATP1B1 ECM: closed the FLUX-1 auto-ECM xfail; +BSA PSu,inf formally deferred (data-blocked)
+
+A 3-agent investigation of "the one un-foreclosed accuracy lever" (diagnosis §9 — the +BSA /
+albumin-mediated PSu,inf OATP correction, Li/Benet 2020) found the re-anchor already shipped and
+the lever headline-inert, and closed its last test loose end:
+
+- **Re-anchor already done** (#66, 2026-06-04): OATP1B1 abundance 5.0e5 → 1.3e5, calibrated on
+  pitavastatin (non-holdout), pravastatin demoted to validation-only (Invariant #5 restored).
+  `test_oatp_ecm_statins[pravastatin, pitavastatin]` were already un-xfailed and passing.
+- **Closed the last loose end (#103):** `test_predict_auto_ecm.py` still pinned two auto-ECM Cmax
+  values (0.0294 / 0.00116) computed under the old 5.0e5 abundance — 53% / 90% stale under the live
+  1.3e5, so both tests were xfailed. Their purpose is mechanical (auto-activation fires, warning
+  emitted), and Cmax accuracy is already guarded by the sibling `test_oatp_ecm_statins.py`, so the
+  fragile exact pins were replaced with that sibling's **stack-robust fold-error gate** (pravastatin
+  FE<3.0, pitavastatin FE<3.2) and un-xfailed. Verified public-clone deterministic: pravastatin Cmax
+  0.0450 (FE 1.00), pitavastatin 0.0022 (FE 1.58); all 4 tests pass strict.
+- **+BSA PSu,inf formally deferred (DE-44):** the mechanistic upgrade (replace `hepatic_ecm.json`
+  seed PS midpoints with Li/Benet 2020 +BSA-derived PSu,inf, then re-derive abundance) is
+  **data-blocked** — the per-substrate PSu,inf/Kp values are in the paywalled AAPS J primary source
+  ([DOI](https://doi.org/10.1208/s12248-020-00528-y)), not to be fabricated — and near-zero-observable
+  (the abundance re-anchor absorbs the PS change; only *relative* statin shifts; pravastatin is
+  validation-only) on top of headline-inert. Deferred until the primary-source table is available.
+
+No headline change (2.743). The engine's OATP1B1 ECM is correct and tested; the residual is
+provenance (seed vs +BSA PS), not accuracy — a third correctness-not-accuracy finding this cycle,
+after the RBP honest-1.0 fix and the prospective re-score.
+
 ## 2026-07-05 — Prospective N=28 re-scored on the current engine: FLUX-1 does not improve OOD Cmax (DE-54)
 
 Re-ran the 2026-06-01 public-clone prospective set (28 single-agent oral SM 2024-2025 FDA NMEs)