fix(awooop): use db-safe timestamps for alert mirrors

apps/api/src/services/channel_hub.py

@@ -49,6 +49,11 @@ _INTERIM_WAIT_SECONDS = 30
 _OUTBOUND_REDACTION_VERSION = "audit_sink_v1"
 
 
+def _db_timestamp_now() -> datetime:
+    """Return UTC now in the timestamp shape accepted by the production DB path."""
+    return datetime.now(UTC).replace(tzinfo=None)
+
+
 def _input_sha256(input_payload: dict[str, Any] | None) -> str | None:
     """計算 Run input 的穩定 hash，讓 mirror run 也能保留最小完整性證據。"""
     if not input_payload:
@@ -459,7 +464,7 @@ async def record_grouped_alert_event(
                 channel_chat_id=f"alert-group:{group_key}",
                 content_type="text",
                 raw_content=content,
-                provider_ts=datetime.now(UTC),
+                provider_ts=_db_timestamp_now(),
                 run_id=run_id,
             )
 
@@ -576,7 +581,7 @@ async def record_alertmanager_event(
                 channel_chat_id=f"alertmanager:{namespace or 'default'}",
                 content_type="text",
                 raw_content=content,
-                provider_ts=datetime.now(UTC),
+                provider_ts=_db_timestamp_now(),
                 run_id=run_id,
                 is_duplicate=is_duplicate,
             )
@@ -648,7 +653,7 @@ async def record_outbound_message(
 
     actual_status = "shadow" if is_shadow else send_status
     sent_at = (
-        datetime.now(UTC).replace(tzinfo=None)
+        _db_timestamp_now()
         if actual_status == "sent"
         else None
     )

apps/api/tests/test_channel_hub_grouped_alert_events.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from src.services.channel_hub import (
+    _db_timestamp_now,
     build_alertmanager_provider_event_id,
     build_alertmanager_run_id,
     build_grouped_alert_provider_event_id,
@@ -13,6 +14,10 @@ from src.services.channel_hub import (
 )
 
 
+def test_db_timestamp_now_is_naive_utc_for_asyncpg() -> None:
+    assert _db_timestamp_now().tzinfo is None
+
+
 def test_build_grouped_alert_provider_event_id_is_deterministic() -> None:
     event_id = build_grouped_alert_provider_event_id(
         "INC-20260507-ABCD12",