harness(causality): guardia look-ahead + calendar-artifact self-policing nel lab intraday

- altlib.causality_ok(target_fn, tf): online-consistency guard (ricalcola il target su un
  prefisso, la coda deve combaciare col full). eval_weights shifta la posizione ma non vede
  una feature non-causale (finestra centrata/shift(-k)/stat full-sample) -> questa sì.
- intra_score integra DUE gate prima/dopo lo scoring: causality (leak -> LEAK, squalificato)
  e day_boundary_robust (ARTIFACT-RISK -> fuori dagli slot). Effetto sul leaderboard intraday:
  open_drive + weekly_seasonality + overnight -> CAL-ARTIFACT (da soli, niente skeptic);
  prevday_range_breakout resta (ROBUST). earns_slot 10 -> 8.
- +2 test (causal-ok / leak), suite intera verde.

Il lab intraday ora auto-becca leak e artefatti-calendario che ieri richiedevano 3 scettici.
Chiude la 3a lezione harness dell'onda intraday.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/research/intraday/intra_score.py

@@ -40,6 +40,15 @@ def score(path: Path, tf: str) -> dict:
         target = _target(path)
     except Exception as e:
         return {**rec, "error": f"import: {e}", "earns_slot": False}
+    # LOOK-AHEAD guard first: eval_weights' shift can't catch a non-causal FEATURE (centered
+    # window / shift(-k) / full-sample stat). A leak is disqualified no matter its Sharpe.
+    try:
+        caus = al.causality_ok(target, tf=tf)
+        rec["causal"] = bool(caus["ok"])
+        if not caus["ok"]:
+            return {**rec, "causality": caus, "marginal_verdict": "LEAK", "earns_slot": False}
+    except Exception as e:
+        return {**rec, "error": f"causality: {e}", "causal": False, "earns_slot": False}
     try:
         rep = al.study_marginal(path.stem, target, tf=tf)
     except Exception as e:
@@ -64,6 +73,17 @@ def score(path: Path, tf: str) -> dict:
         turnover_per_year=round(turn, 1), fee020_full_sharpe=round(fee020, 3),
         fee_survives=cell.get("fee_survives"),
     )
+    # calendar-artifact guard: a signal whose marginal uplift INVERTS under a UTC day-boundary
+    # shift is a labeling artifact (open_drive), not an intraday effect. INVARIANT (price
+    # signal) and ROBUST (genuine calendar effect, e.g. prevday breakout) pass.
+    try:
+        db = al.day_boundary_robust(target, tf=tf)
+        rec["boundary_verdict"] = db["verdict"]
+        rec["boundary_spread"] = db["spread"]
+        if db["verdict"] == "ARTIFACT-RISK":
+            rec["earns_slot"] = False
+    except Exception as e:
+        rec["boundary_verdict"] = f"err:{e}"
     return rec
 
 
@@ -85,10 +105,14 @@ def main():
         for r in rows:
             if "error" in r:
                 print(f"  {r['name'][:26]:<26}{r['tf']:>4} ERROR {r['error'][:40]}"); continue
+            if r.get("causal") is False:
+                print(f"  {r['name'][:26]:<26}{r['tf']:>4} LEAK (look-ahead, disqualified) "
+                      f"max_tail_diff={r.get('causality', {}).get('max_tail_diff')}"); continue
+            bflag = " CAL-ARTIFACT" if r.get("boundary_verdict") == "ARTIFACT-RISK" else ""
             print(f"  {r['name'][:26]:<26}{r['tf']:>4} {str(r['marginal_verdict']):<9}"
                   f"{str(r['abs_grade']):>5}{str(r.get('corr_hold')):>6}{str(r.get('uplift_hold')):>6}"
                   f"{str(r.get('cand_insample_sharpe')):>6}{str(r.get('turnover_per_year')):>6}"
-                  f"{str(r.get('fee020_full_sharpe')):>7}  {'<<<' if r.get('earns_slot') else ''}")
+                  f"{str(r.get('fee020_full_sharpe')):>7}  {'<<<' if r.get('earns_slot') else bflag}")
         slots = [r["name"] for r in rows if r.get("earns_slot")]
         print(f"\n  EARNS SLOT: {slots or 'NONE'}")
         (HERE / "intra_leaderboard.json").write_text(json.dumps(rows, indent=2, default=str))