feat(engineering): enforce V1-0 write invariants

tests/test_engineering_v1_phase5.py

@@ -143,8 +143,11 @@ def test_requirement_name_conflict_detected(tmp_data_dir):
     r2 = create_entity("requirement", "Surface figure < 25nm",
                       project="p-test", description="Different interpretation")
 
-    detected = detect_conflicts_for_entity(r2.id)
-    assert len(detected) == 1
+    # V1-0 synchronous hook: the conflict is already detected at r2's
+    # create-time, so a redundant detect call returns [] due to
+    # _record_conflict dedup. Assert on list_open_conflicts instead —
+    # that's what the intent of this test really tests: duplicate
+    # active requirements surface as an open conflict.
     conflicts = list_open_conflicts(project="p-test")
     assert any(c["slot_kind"] == "requirement.name" for c in conflicts)
 
@@ -191,8 +194,12 @@ def test_conflict_resolution_dismiss_leaves_entities_alone(tmp_data_dir):
                       description="first meaning")
     r2 = create_entity("requirement", "Dup req", project="p-test",
                       description="second meaning")
-    detected = detect_conflicts_for_entity(r2.id)
-    conflict_id = detected[0]
+    # V1-0 synchronous hook already recorded the conflict at r2's
+    # create-time. Look it up via list_open_conflicts rather than
+    # calling the detector again (which returns [] due to dedup).
+    open_list = list_open_conflicts(project="p-test")
+    assert open_list, "expected conflict recorded by create-time hook"
+    conflict_id = open_list[0]["id"]
 
     assert resolve_conflict(conflict_id, "dismiss")
     # Both still active — dismiss just clears the conflict marker