test: sync PG telemetry integration helpers with 1.3.8 stall columns

_minimal_fields and the pre_135 acceptance dicts missed the two new
columns, KeyErroring against migrated 39-column physical tables
(caught by the pre-merge integration gate; production path is
signature-gated and unaffected). Verifier gaps P2-1/P2-2 closed:
full suite 1764 passed, PG 30 passed, lint green.

tests/integration/test_postgres_telemetry.py

@@ -170,6 +170,9 @@ def _minimal_fields(call_id: str | None = None, **overrides) -> dict[str, object
         # 逻辑快照两列只属终态行
         "attempts": None,
         "total_latency_ms": None,
+        # —— 1.3.8 两列: 沉默归因只属流式 chat 成功 attempt 行(issue #27),普通行 NULL ——
+        "stall_ms": None,
+        "stall_count": None,
     }
     fields.update(overrides)
     return fields
@@ -1103,7 +1106,7 @@ class TestCallObservabilityColumnsAcceptance:
     """
 
     async def test_pre_135_table_gains_the_ten_columns_and_old_rows_stay_null(self, pre_135_schema):
-        """27 列旧表 auto 补齐到 37 列,新行两类取值读得回,**历史行十列一律 NULL**。
+        """27 列旧表 auto 补齐到 39 列(1.3.5 十列 + 1.3.8 两列),新行两类取值读得回,**历史行新增列一律 NULL**。
 
         旧行不回填是本版的明示决策(设计 §5): NULL 表达的是"补列之前根本没记过
         这件事",与任何哨兵值都不是一回事。若哪天有人给这十列加了 DEFAULT,历史行
@@ -1170,6 +1173,9 @@ class TestCallObservabilityColumnsAcceptance:
                 "error_body": "upstream said 503",
                 "attempts": None,
                 "total_latency_ms": None,
+                # 1.3.8 两列: 普通成功 attempt 行无沉默观测 → NULL
+                "stall_ms": None,
+                "stall_count": None,
             }
             assert dict(by_id["term"]) == {
                 "call_id": "term",
@@ -1183,6 +1189,9 @@ class TestCallObservabilityColumnsAcceptance:
                 "error_body": None,
                 "attempts": 3,
                 "total_latency_ms": 4200,
+                # 1.3.8 两列: 终态行无 transport 观测 → NULL
+                "stall_ms": None,
+                "stall_count": None,
             }
             # 历史行: 十列逐列 NULL(整体比对,漏掉任一列都红)
             assert dict(by_id["pre135"]) == {