fix(evidence): reconcile generations safely

harness/tests/l0/test_pgvector_store.py

@@ -79,6 +79,13 @@ def vector_configs():
                     f"GRANT INSERT, UPDATE ON vectors.{table} "
                     "TO vector_l0_writer, vector_l0_no_sequence"
                 )
+                if table == "evidence":
+                    connection.exec_driver_sql(
+                        "GRANT DELETE ON vectors.evidence TO vector_l0_writer"
+                    )
+                    connection.exec_driver_sql(
+                        "GRANT SELECT (kind, metadata) ON vectors.evidence TO vector_l0_writer"
+                    )
                 connection.exec_driver_sql(
                     f"GRANT SELECT (record_key, kind, content_hash) "
                     f"ON vectors.{table} TO vector_l0_writer, vector_l0_no_sequence"
@@ -118,6 +125,21 @@ def test_pgvector_round_trip_hash_and_upsert(store):
     assert store.search(["memory"], [0.8, 0.2], limit=1)[0].id == "record:a"
 
 
+def test_pgvector_lists_and_deletes_exact_evidence_generation(store):
+    generation = "gen:" + "a" * 32
+    value = VectorWriteRecord(
+        record=VectorRecord(
+            id="evidence-generation-a", kind="evidence", ref="doc:a", title="a",
+            content="content", metadata={"vector_generation": generation},
+        ),
+        embedding=[1.0, 0.0], content_hash="sha256:" + "a" * 64,
+    )
+    store.upsert("evidence", [value])
+    assert generation in store.list_evidence_generations("evidence")
+    assert store.delete_generation("evidence", generation) == 1
+    assert generation not in store.list_evidence_generations("evidence")
+
+
 def test_pgvector_search_filters_kinds_before_limit(store):
     store.upsert("memory", [_record("solved", [1.0, 0.0], kind="solved_question")])
     hits = store.search("memory".split(), [1.0, 0.0], limit=1, kinds=["memory"])

harness/tests/l0/test_vector_adapter_parity.py

@@ -250,3 +250,17 @@ def test_http_delete_generation_legacy_404_fails_closed_without_body_leak(monkey
     with pytest.raises(VectorRestError, match="delete_vector_generation RPC is unavailable") as error:
         client.delete_generation("evidence", "gen:" + "a" * 32)
     assert "secret" not in str(error.value)
+
+
+def test_http_list_evidence_generations_exact_rpc_and_legacy_fail_closed(monkeypatch):
+    calls = []
+    monkeypatch.setattr(
+        "tht.vectorstore.rest_client.requests.post",
+        lambda url, json, **kwargs: calls.append((url, json)) or Response([
+            {"generation": "gen:" + "a" * 32}
+        ]),
+    )
+    client = VectorRestClient(RestConfig(base_url="https://vectors.test", api_key="writer"))
+    assert client.list_evidence_generations("evidence") == ["gen:" + "a" * 32]
+    assert calls[0][0].endswith("/rpc/list_evidence_generations")
+    assert calls[0][1] == {"table_name": "evidence", "kind": "evidence"}