feat(delivery): add GitHub private backup evidence gate

apps/api/tests/test_delivery_closure_workbench_api.py

@@ -17,7 +17,7 @@ def test_delivery_closure_workbench_endpoint_returns_product_summary():
     data = response.json()
     assert data["schema_version"] == "delivery_closure_workbench_v1"
     assert data["summary"]["source_count"] == 5
-    assert 4 <= data["summary"]["loaded_source_count"] <= 5
+    assert data["summary"]["loaded_source_count"] == 5
     assert data["summary"]["runtime_execution_authorized"] is False
     assert data["summary"]["remote_write_authorized"] is False
     assert data["summary"]["repo_creation_authorized"] is False
@@ -35,10 +35,13 @@ def test_delivery_closure_workbench_endpoint_returns_product_summary():
     assert lanes["gitea"]["metric"]["kind"] == "workflow_count"
     assert lanes["runtime"]["metric"]["kind"] == "surface_count"
     assert lanes["backup"]["metric"]["kind"] == "readiness_row_count"
-    if sources["github_private_backup"]["loaded"] is False:
-        assert lanes["github"]["blocker_count"] == 1
-        assert lanes["github"]["status"] == "blocked_github_private_backup_source_missing"
-        assert sources["github_private_backup"]["missing_reason"]
+    assert sources["github_private_backup"]["loaded"] is True
+    assert sources["github_private_backup"]["schema_version"] == "github_target_private_backup_evidence_gate_v1"
+    assert sources["github_private_backup"]["missing_reason"] == ""
+    assert lanes["github"]["blocker_count"] == 9
+    assert lanes["github"]["status"] == "blocked_public_visibility_and_safe_credential_evidence_required"
+    assert lanes["github"]["metric"]["verified"] == 0
+    assert lanes["github"]["metric"]["total"] == 9
     assert all(0 <= lane["completion_percent"] <= 100 for lane in lanes.values())
     assert all(lane["tone"] in {"ok", "warn", "danger"} for lane in lanes.values())