Add H2 order-control seed policy

docs/evidence/h2-output-cloud-geometry-20260525.md

@@ -99,6 +99,13 @@ class-ordered sampling effect。
 如果需要推进，最多释放一个有界 order-control / reseeded / interleaved
 response-cache scout，用来判断该强信号是否跨 class-order 控制保留。
 
+当前允许的最小脚本改动仅限于生成这个控制 cache：
+`scripts/run_h2_response_strength_validation.py --seed-offset-policy shared-position`。
+该模式会让 member / nonmember 使用相同 per-position seed offset，并在
+`summary.json` 中标记 `order_control_scout = true`。它只用于重新评估
+class-ordered sampling effect，不代表 admission，也不得直接生成 Platform /
+Runtime row。
+
 ## Decision
 
 `candidate complementary signal / order-control required / no admitted row`。

scripts/run_h2_response_strength_validation.py

@@ -62,6 +62,15 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument("--bootstrap-iters", type=int, default=200)
     parser.add_argument("--frequency-cutoff", type=float, default=0.5)
     parser.add_argument("--primary-scorer", choices=PRIMARY_SCORERS, default="raw_h2_logistic")
+    parser.add_argument(
+        "--seed-offset-policy",
+        choices=("class-ordered", "shared-position"),
+        default="class-ordered",
+        help=(
+            "class-ordered preserves the original member/nonmember contiguous seed offsets; "
+            "shared-position uses the same per-position seed sequence for both classes as an order-control scout."
+        ),
+    )
     parser.add_argument("--no-save-responses", action="store_true")
     return parser.parse_args()
 
@@ -81,6 +90,16 @@ def _validate_args(args: argparse.Namespace) -> list[int]:
     return timesteps
 
 
+def seed_offsets_for_policy(policy: str, *, member_count: int) -> tuple[int, int]:
+    """Return member and nonmember seed offsets for the requested control policy."""
+
+    if policy == "class-ordered":
+        return 0, int(member_count)
+    if policy == "shared-position":
+        return 0, 0
+    raise ValueError(f"Unknown seed offset policy: {policy}")
+
+
 def main() -> int:
     args = parse_args()
     timestamp = datetime.now().strftime("%Y%m%d-%H%M%S")
@@ -127,6 +146,10 @@ def main() -> int:
             packet_indices=nonmember_indices,
             batch_size=args.batch_size,
         )
+        member_seed_offset, nonmember_seed_offset = seed_offsets_for_policy(
+            args.seed_offset_policy,
+            member_count=len(member_indices),
+        )
 
         member_inputs, member_responses, member_distances = collect_strength_responses(
             model,
@@ -137,7 +160,7 @@ def main() -> int:
             repeats=args.repeats,
             denoise_stride=args.denoise_stride,
             seed=args.seed,
-            sample_offset=0,
+            sample_offset=member_seed_offset,
         )
         nonmember_inputs, nonmember_responses, nonmember_distances = collect_strength_responses(
             model,
@@ -148,7 +171,7 @@ def main() -> int:
             repeats=args.repeats,
             denoise_stride=args.denoise_stride,
             seed=args.seed,
-            sample_offset=len(member_indices),
+            sample_offset=nonmember_seed_offset,
         )
 
         labels = np.concatenate(
@@ -216,6 +239,7 @@ def main() -> int:
             raw_best_simple_auc=raw_best_simple_auc,
         )
         validation_passed = bool(validation_gate["validation_passed"])
+        is_order_control_scout = args.seed_offset_policy != "class-ordered"
         summary = {
             "status": "ready",
             "task": "H2 response-strength validation",
@@ -235,6 +259,9 @@ def main() -> int:
                 "repeats": int(args.repeats),
                 "denoise_stride": int(args.denoise_stride),
                 "seed": int(args.seed),
+                "seed_offset_policy": args.seed_offset_policy,
+                "member_seed_offset": int(member_seed_offset),
+                "nonmember_seed_offset": int(nonmember_seed_offset),
                 "frequency_cutoff": float(args.frequency_cutoff),
                 "primary_scorer": args.primary_scorer,
             },
@@ -257,11 +284,19 @@ def main() -> int:
                 "validation_gate": validation_gate,
                 "validation_passed": bool(validation_passed),
                 "promotion_allowed": False,
+                "order_control_scout": bool(is_order_control_scout),
             },
-            "verdict": "positive but bounded validation" if validation_passed else "negative but useful",
+            "verdict": (
+                "order-control scout generated"
+                if is_order_control_scout
+                else "positive but bounded validation"
+                if validation_passed
+                else "negative but useful"
+            ),
             "notes": [
                 "This runner is a stable successor to archived H2 X-run scripts.",
                 "A positive result remains candidate evidence until cross-asset or stronger black-box comparator review.",
+                "Non-default seed offset policies are control-cache scouts only and do not admit a Runtime job.",
             ],
         }
     except Exception as exc:

tests/test_run_h2_response_strength_validation.py

@@ -0,0 +1,26 @@
+import unittest
+from unittest.mock import patch
+
+from scripts.run_h2_response_strength_validation import parse_args, seed_offsets_for_policy
+
+
+class RunH2ResponseStrengthValidationTests(unittest.TestCase):
+    def test_default_seed_offset_policy_preserves_existing_cache_shape(self) -> None:
+        with patch("sys.argv", ["run_h2_response_strength_validation.py"]):
+            args = parse_args()
+
+        self.assertEqual(args.seed_offset_policy, "class-ordered")
+
+    def test_class_ordered_policy_preserves_original_offsets(self) -> None:
+        self.assertEqual(seed_offsets_for_policy("class-ordered", member_count=512), (0, 512))
+
+    def test_shared_position_policy_uses_same_offsets_for_both_classes(self) -> None:
+        self.assertEqual(seed_offsets_for_policy("shared-position", member_count=512), (0, 0))
+
+    def test_unknown_policy_is_rejected(self) -> None:
+        with self.assertRaisesRegex(ValueError, "Unknown seed offset policy"):
+            seed_offsets_for_policy("bad-policy", member_count=512)
+
+
+if __name__ == "__main__":
+    unittest.main()