fix(awooop): store outbound sent timestamp as naive utc

apps/api/src/services/channel_hub.py

@@ -489,7 +489,11 @@ async def record_outbound_message(
     source_envelope_json = json.dumps(envelope, ensure_ascii=False, default=str)
 
     actual_status = "shadow" if is_shadow else send_status
-    sent_at = datetime.now(UTC) if actual_status == "sent" else None
+    sent_at = (
+        datetime.now(UTC).replace(tzinfo=None)
+        if actual_status == "sent"
+        else None
+    )
 
     await ensure_completed_shadow_run(
         db,

apps/api/tests/test_channel_hub_grouped_alert_events.py

@@ -135,3 +135,4 @@ async def test_record_outbound_message_sets_sent_at_for_sent_messages() -> None:
     assert ":sent_at" in insert_statement
     assert session.param_sets[-1]["send_status"] == "sent"
     assert session.param_sets[-1]["sent_at"] is not None
+    assert session.param_sets[-1]["sent_at"].tzinfo is None

docs/LOGBOOK.md

@@ -7308,5 +7308,6 @@ OK
 
 - rollback transaction smoke 抓到 asyncpg bind parameter 型別推論問題：`CASE WHEN :send_status = 'sent'` 會被推成 text/varchar ambiguous。
 - 第一版 `CAST(:send_status AS text)` 仍會因同一 bind param 同時插入 varchar 與比較而 ambiguous；最終改成 Python 端計算 `sent_at` 參數，SQL 只插入 `:sent_at`，避免 outbound mirror 在 production 寫入時失敗。
+- 第二次 rollback smoke 抓到 DB 欄位是 `timestamp without time zone`，已改成 naive UTC `datetime.now(UTC).replace(tzinfo=None)`，避免 asyncpg timezone-aware bind 失敗。
 
 **目前整體進度**：約 69%。