Add harness candidate set audit

tests/test_core_flow.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+import hashlib
 import contextlib
 import io
 import math
@@ -1803,6 +1804,33 @@ class CoreFlowTests(unittest.TestCase):
                 window_summary={"prompt_tokens_p95": 2048},
                 state=state,
             )
+            candidate_set = context["experiment_plan"]["candidate_set"]
+            self.assertEqual(candidate_set["version"], "candidate-set-v1")
+            self.assertIn("candidate_set_hash", candidate_set)
+            self.assertGreaterEqual(
+                candidate_set["blocked_reason_summary"].get(
+                    "blocked_noop_or_repeat_effective_full_config",
+                    0,
+                ),
+                1,
+            )
+            baseline_fingerprint = hashlib.sha256(
+                _effective_config_signature(
+                    study,
+                    {"env_patch": {}, "flag_patch": {}},
+                ).encode("utf-8")
+            ).hexdigest()
+            blocked_baseline_equivalent = [
+                item
+                for item in candidate_set["blocked_candidates"]
+                if item.get("effective_config_fingerprint") == baseline_fingerprint
+            ]
+            self.assertTrue(blocked_baseline_equivalent)
+            self.assertEqual(
+                blocked_baseline_equivalent[0]["blocked_reason"],
+                "blocked_noop_or_repeat_effective_full_config",
+            )
+            self.assertIn("effective_config_fingerprint", blocked_baseline_equivalent[0])
             actions = context["experiment_plan"]["candidate_actions"]
             self.assertFalse(
                 any(