experiment(sp22): H1 — pin aux pred horizon at 200 bars (atomic)

Hypothesis test for SP22 H1 (label horizon mismatch).

Finding from v9/v10 HEALTH_DIAG: aux_dir_acc=28-47% (BELOW RANDOM)
across all observed cycles. Root cause: adaptive aux_horizon_update
collapses H back to ~1.7 bars (observed avg winning hold time),
making the aux label HFT microstructure noise.

Experiment:
  1. Bump SENTINEL_AUX_PRED_HORIZON_BARS 60.0 → 200.0
  2. Disable launch_aux_horizon_chain call so H stays at sentinel

Predicted: if aux_dir_acc rises >50% → H1 confirmed; if stays ≤50%
→ escalate to H2/H4 per SP22 plan.

Cost: 1 smoke ~30min, kill early on cycle 1-2 trend.

Files changed:
  - crates/ml/src/cuda_pipeline/sp14_isv_slots.rs
  - crates/ml/src/trainers/dqn/trainer/training_loop.rs
  - docs/dqn-wire-up-audit.md (H1 experiment entry)

Reverts if H1 falsified.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/dqn-wire-up-audit.md

@@ -16210,3 +16210,48 @@ configuration. New SP arc needed:
 - **Validation method**: each hypothesis gets its own atomic smoke
   with one variable changed; compare against v9 baseline (174 peak val,
   WR=50.1%).
+
+## 2026-05-12 — SP22 H1 experiment: pin aux horizon at 200 bars
+
+### Hypothesis
+
+`aux_dir_acc` pins at 28-47% (BELOW RANDOM) across v9/v10 cycles
+because the adaptive `aux_horizon_update_kernel` collapses
+ISV[AUX_PRED_HORIZON_BARS_INDEX=450] back to ~1.7 bars (the observed
+`avg_winning_hold_time`). The aux head label becomes
+`(p[bar+2] > p[bar])` — HFT-scale microstructure noise. With unlearnable
+labels, the supervised aux supervision can't teach directional features
+to the trunk → the WR=50% plateau in v5-v9.
+
+### Experiment scope
+
+1. Bump `SENTINEL_AUX_PRED_HORIZON_BARS` from 60.0 → 200.0
+   (~156s @ volume bars at 0.78s/bar — multi-bar context window).
+2. Disable `launch_aux_horizon_chain` call so H stays pinned at the
+   sentinel throughout training.
+
+### Predicted outcomes
+
+- H1 CONFIRMED if `aux_dir_acc` rises above 50% at H=200. Fix: replace
+  adaptive H with a fixed long horizon, or change H's driver from
+  avg_win_hold_time to something less collapsible.
+- H1 FALSIFIED if `aux_dir_acc` stays ≤50% at H=200. Aux head can't
+  learn direction at any horizon — escalate to SP22 H2 (action-space
+  pathology) or H4 (feature representation gap).
+
+### Files changed
+
+- `crates/ml/src/cuda_pipeline/sp14_isv_slots.rs`:
+    `SENTINEL_AUX_PRED_HORIZON_BARS: 60.0 → 200.0`
+- `crates/ml/src/trainers/dqn/trainer/training_loop.rs`:
+    `launch_aux_horizon_chain` call DISABLED (preserves sentinel).
+
+### Cost + kill criteria
+
+1 smoke, ~30 min wall-clock. Kill at cycle 2 if `aux_dir_acc` trend
+is clear (per `feedback_kill_runs_on_anomaly_quickly`).
+
+### Reverts
+
+If H1 falsified → revert both files, proceed to H2/H3/H4 per the SP22
+plan at `docs/plans/2026-05-12-sp22-wr-plateau-investigation.md`.